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THE 
SCHOOL HOUSE 

Its 

Heating and Ventilation 



BY 

JOSEPH A. MOORE 

INSPECTOR OF PUBLIC BUILDINGS 
STATE OF MASSACHUSETTS 



!9 5 








LIBRARY of CONGRESS 
Two Copies Received 

NOV 25 1905 

Copyright Entry 

CIASS O. XXc. No. 

COPY B. 



Copyrighted, 1905 
Bv Joseph A. Moore 



Published by the Author 
Boston, Mass. 



GRIFFITH -STILLINGS PRESS 
368 CONGRESS ST.- BOSTON 



INTRODUCTION 



The writer having been for the last eighteen years engaged in 
the inspection of public buildings in Massachusetts, and in super- 
vising the construction of and testing the various methods of heat- 
ing and ventilation, especially in schoolhouses, presents to those 
interested in our public schools some suggestions as to the construc- 
tion and the heating and ventilation of such buildings. The class 
of buildings selected are those of small or moderate size, of which 
many are erected each year. 

It is not the writer's intention to give theoretical or scientific 
descriptions or arguments, but simply such methods and plans as 
have been proved by actual experience to give satisfactory results. 

Many of the plans were designed by the writer for the annual 
official reports of the late Rufus R. Wade, Chief of the Massachu- 
setts District Police 

The method of setting up indirect radiators, as shown in the 
plans and now generally adopted in Massachusetts, was designed by 
the writer, and first published in drawings which formed part of 
the official exhibit of the Inspection Department of the Massachu- 
setts District Police at the Columbian Exposition at Chicago in 1S93, 
and for which an award was given. 

Other plans formed part of the exhibit at the Paris Exposition in 
1900, for which an award was also given, and at the Louisiana 
Purchase Exposition at St. Louis in 1904, for which a gold medal 
was also awarded the department. 

Boston, Mass. 
1905. 



CONTENTS. 



PART I. 



Chapter I — The schoolhouse, location, size and cost, building 
committee, plans, Massachusetts laws, appropriation, choice 
of site, height, construction, prevention of spread of fire, 
means to extinguish fire, basement, corridors, vestibules, exits, 
stairways, fire escapes, doors, windows, class rooms, seating, 
blackboards, clocks, thermometers, pictures and plaster casts, 
telephones and fire-alarm boxes. 

Chapter II — Air, composition, impurities, respiration, products 
of respiration, amount of air required, humidity, lights, test- 
ing purity of air, Wolpert's test, preparation of lime water, 
measurement of air, wind velocity and pressure. 

Chapter III — i\mount of air required by Massachusetts regula- 
tions, some erroneous ideas of ventilation, circulation of air, 
u systems," location of inlets and outlets, exhaust and plenum 
methods, leakage, velocity, beams and projections below ceil- 
ing, ceiling ventilation in halls, location of heating apparatus, 
deflectors, mixing clampers, dampers in vent flues, flap valves, 
force and direction of prevailing winds, adjustable switch 
dampers, location of discharge from vent flues, back draft, 
caps on vent flues, testing movement of air currents. 

Chapter IV" — Tests of amount of air supply and heat in school- 
rooms, difference in cost of heating schoolhouses, size and 
construction of warm air ducts and flues, wire grills, cast-iron 
registers, mixing dampers, adjusting dampers, aspirating 
chimneys and vent flues, heat in vent flues, location of vent 
flue heaters, exhaust fans, amount of steam heat in vent flues, 
size and location of vent openings, chimneys, location, height 
and area. 

Chapter V — Boilers, horse-power, grate surface, heating surface, 
determining size of boiler, shell, heads, tubes, braces, fittings 
and appliances, standard sizes, setting smoke flues, U.S. 
Government rule for safe pressure, Massachusetts inspectors' 
rule, water-tube boilers, upright, tubular, sectional cast-iron, 
Massachusetts inspectors' requirements for fittings, Massachu- 



vi CONTENTS. 

setts law for licensing of engineers and firemen and for the 
inspection of steam boilers. 

Chapter VI — Steam-pipes, size, covering, valves, locating pipes, 
radiators, quantity, location, casing radiators, rule for calcu- 
lating amount of indirect radiation, automatic heat control. 

Chapter VII — Furnaces, use in small buildings, location, con- 
struction, size, wrought and cast-iron, test for gas leakage, 
brick setting, portable type, smoke-pipes, pit, air supply and 
mixing valves, location as to air supply, cold air rooms, com- 
bination of furnace and steam heating, twin connected furnaces, 
combination of furnace and hot water heating, fans for supply- 
ing air to furnaces, electric motors, gas engines, water-motors. 

Chapter VIII — Janitors, duties and instructions for care and 
management of heating and ventilating appliances in school- 
houses. 

Chapter IX — Sanitary appliances in schoolhouses, outside sani- 
tary buildings. 

PART II. 

Plate I — Plan and description of one-room schoolhouse, showing 
method of heating and ventilating. 

Plates II and III — Plan, sections and description of one-room 
portable schoolhouse, showing heating, ventilating apparatus 
and circulation of air. 

Plates IV, V and VI — Plans and description of two-room, one- 
story schoolhouse, with sections of heating and ventilating 
-apparatus and circulation of air. 

Plates VII, VIII, and IX — Plans and description of two-room, 
two-story schoolhouse, and section through ventilating shaft. 

Plates X, XI, XII, XIII and XIV — Plans and description of four- 
room, two-story schoolhouse, showing fan and furnace and 
sections through warm air and vent flues. 

Plates XV, XVI and XVII — Plans and description of five-room 
two-story schoolhouse, steam heated. 

Plates XVIII, XIX and XX — Plans and description of six-room, 

two-story schoolhouse, with combination of furnace and 

steam heating. 
Plates XXI, XXII, XXIII and XXIV— Plans and description of 

seven-room, two-story grammar schoolhouse, with sections of 

steam heating and ventilating apparatus. 



CONTENTS. vii 

Plates XXV, XXVI, XXVII and XXVIII — Plans and descrip- 
tion of eight-room, two-story schoolhouse, showing steam 
heating by combination of a fan and a gravity air supply. 

Plates XXIX, XXX, XXXI and XXXII— Plans and description 
of an eight-room, two-story school, steam heated. 

Plates XXXIII, XXXIV and XXXV— Plans and description of 
small two-story high school, steam heated. 

Plates XXXVI and XXXVII— Plans for sanitary buildings. 

Plate XXXVIII — Plan, section and description of a direct-indirect 
(steam) radiator. 

Plate XXXIX — Plan, section and description of portable furnace 
setting for small hall or church. 

Plate XL — Section and description of foot- warmer for school- 
house corridor. 

Plate XLI — Setting for one horizontal tubular boiler. 

Plates XLII and XLIII — Sections of setting for one horizontal 

tubular boiler. 
Plate XLIV — Section of setting for two horizontal tubular boilers. 

Figures. 

Numbers 1 to 9. — Schoolhouse furniture. 

10 — Prof. Wolpert's air tester. 

11 — Lime water apparatus. 

12 — Template for correcting anemometer blades. 

13 — Form of air inlet in schoolroom. 

14 — Form of air inlet in schoolroom. 

J 5, 16, 17 and 18 — Position of anemometer in measuring 
air. 

19, 20 and 21 — Location of inlets and outlets and cir- 
culation of air in schoolrooms. 

Tables. 

1 — For Wolpert's air test. 

2 — Of wind velocity and pressure. 

3 — Of tests of amount of heat and air in schoolhouses. 
4 — Of tests of amount of heat and air in schoolhouses. 

5 — Of tests of amount of heat and air in schoolhouses. 

6 — Of tests of amount of heat and air in schoolhouses. 



viii CONTENTS. 

7 — Relative cost of fuel in schoolhouses. 

8 — Of boiler, grate and heating surfaces. 

9 — Of area of grate surface and tube opening. 

10 — Of standard boiler tubes. 

11 — Of standard sizes of boilers. 

12 — Of dimensions of brick settings for boilers. 

13 — Of dimensions of brick settings for boilers. 

14 — Of sizes of supply and return steam-pipes. 

15 — Of areas of rectangular openings. 

16 — Of areas and circumference of circles. 
17 — For equalizing diameter of pipes. 

18 — Of number of gallons in round tanks. 

19 — Of capacity of pipes and registers. 

20 — Of weight of steel bars per foot. 
21 — Of standard gauges. 

22 — Of weights of galvanized sheets. 

23 — Of circumferences of circles used by boiler makers. 

24 — Of number of tubes used in return tubular boilers. 

25 — Of dimensions of standard wrought-iron pipe. 

26 — Of expansion of metals. 

27 — For estimating size of coal bins. 



CHAPTER I. 



THE SCHOOL HOUSE. 

WHEN it becomes desirable for a city or town to erect a 
new schoolhouse, some of the first questions to be 
decided are : Where shall it be located, and what is to 
be the size and cost ? 

The first question, as to location, is usually decided by deter- 
mining where is the most convenient place that will best accom- 
modate the greater part of the pupils in the school district. 

The size, by the number of pupils to be provided for, and the 
cost, by the ability or disposition of the city or town to appropriate 
the requisite amount of money for that purpose. 

The choice of location is often a matter of considerable con- 
troversy, and it sometimes, unfortunately, depends upon the power 
or local strength of the contending parties. 

It should, however, be determined which location will best 
serve the interests of the greater number of pupils, and should be 
where it will be free from the objections of noise or unfavorable 
surroundings. 

A site near large manufacturing establishments, or where 
objectionable noises, gases or odors are produced, should be avoided, 
also one where unhealthy conditions may exist. 

A dry and healthy location should be selected in preference to 
one that is low and wet, or on filled ground. 

The size of the building should be determined by the number 
of pupils to be provided for in the district in which the building is 
to be located. Not only the present needs of the district should be 
considered, but also the probable increase in the near future. 

The cost and character of the building will depend consider- 
ably upon the financial ability of the city or town. It is not true 
economy to attempt to build too large a building for too little 
money, or to reduce the cost to such a degree as will necessitate 
the omission of certain essential requisites for a good building. 

Where this is done, dissatisfaction will be the result when the 
building is completed. 

Erecting a large and poorly-constructed building for the sake of 
obtaining a large building at a low cost will in the future prove 



2 THE SCHOOL HOUSE. 

more expensive and unsatisfactory than if a smaller but well-con- 
structed one is built, and the committee having charge of the work 
will eventually receive more blame than thanks for their work. 

When a city or town decides to erect a new schoolhouse, it is 
advisable that a committee be appointed and authorized to procure 
plans, specifications and bona fide estimates of the cost. 

Where possible, the committee should consist of one or more 
practical business men and builders, and also one or more repre- 
sentatives of the school board. 

It is not advisable to appoint too large a committee, as is some- 
times the case. 

With a large committee the actual work is usually done by a few 
members, and discussions often arise which delay the construction. 

A committee of three or five members will often make better 
progress and give better satisfaction than one that is too large. 

After the committee has been appointed it is advisable for them 
to invite a limited number of architects who have had experience 
in schoolhouse construction, to submit competitive plans. The 
invitation should contain a brief description of what is desired ; the 
number and kind of rooms, height and material of which the build- 
ing is to be constructed, whether of brick, stone or wood, the 
location, and also such special features as may be desired. 

The plans submitted should show the system and method of 
heating and ventilation. Where this is not done it is sometimes 
found that a suitable system cannot be installed without making 
changes in the building plans. 

The Massachusetts law requires the plans and specifications for 
schoolhouses to be filed with the State "Inspector of Factories 
and Public Buildings" of the district in which the building is 
located before the building is constructed, and is as follows : 

Chafter 104, Revised La-vus, Massachusetts {igo2~). 

OF THE INSPECTION OF BUILDINGS. 

* ******** 

Specific Requirements. 

Section 22. No building which is designed to be used, in whole or in 
part, as a public building, public or private institution, schoolhouse, church, 
theatre, public hall, place of assemblage or place of public resort, and no 
building more than two stories in height, which is designed to be used 
above the second story, in whole or in part, as a factory, workshop or 
mercantile or other establishment and has accommodations for ten or more 
employees above said story, and no building more than two stories in height 



THE SCHOOL HOUSE. 8 

designed to be used above the second story, in whole or in part, as a hotel, 
family hotel, apartment house, boarding house, lodging house or tenement 
house, and has ten or more rooms above said story, shall be erected until a 
copy of the plans thereof has been deposited with the inspector of factories 
and public buildings for the district in which it is to be erected by the person 
causing its erection, or by the architect thereof. Such plans shall include 
the method of ventilation provided therefor and a copy of such portion of the 
specifications therefor as the inspector may require. Such building shall not 
be so erected without sufficient egresses and other means of escape from fire, 
properly located and constructed. The certificate of the inspector, indorsed 
with the approval of the chief of the district police, shall be conclusive 
evidence of a compliance with the provisions of this chapter unless, after it 
is granted, a change is made in the plans or specifications of such egresses 
and means of escape without a new certificate therefor. Such inspector mav 
require that proper fire stops shall be provided in the floors, walls and 
parti' ions of such building, and may make such further requirements as may 
be necessary or proper to prevent the spread of fire therein or its 
communication from any steam boiler or heating apparatus. 

Section 23. No wooden flue or air duct for heating or ventilating 
purposes shall be placed in any building which is subject to the provisions 
of sections twenty-four and twenty-five and no pipe for conveying hot air or 
steam in such building shall be placed or remain within one inch of any 
woodwork, unless protected to the satisfaction of said inspector by suitable 
guards or casings of incombustible material. 

Section 24. Whoever erects or constructs a building, or an architect or 
other person who draws plans or specifications or superintends the erection 
or construction of a building, in violation of the provisions of this chapter, 
shall be punished by a fine of not less than fifty nor more than one thousand 
dollars. 

Sectiov 25. A building which is used, in whole or in part, as a public 
building, public or private institution, school house, church, theatre, public 
hall, place of assemblage or place of public resort, and a building in which 
ten or more persons are employed above the second story in a factory, work- 
shop, mercantile and other establishment, and a hotel, family hotel, apart- 
ment house, boarding house, lodging house or tenement house in which ten 
or more persons lodge or reside above the second story, and a factory, 
workshop, mercantile or other establishment the owner, lessee or occupant 
of which is notified in writing by an inspector of factories and public build- 
ings that the provisions of this chapter are deemed by him applicable thereto 
shall be provided with proper egresses or other means of escape from fire, 
sufficient for the use of all persons accommodated, assembled, emploved, 
lodged or resident therein ; but no owner, lessee or occupant of such building 
shall be deemed to have violated this provision unless he has been notified 
in writing by such inspector what additional egresses or means of escape 
from fire are necessary and has neglected or refused to supply the same. 
The egresses and means of escape shall be kept unobstructed, in good repair 
and ready for use. Stairways on the outside of the building shall have 
suitable railed landings at each story above the first, accessible at each storv 
from doors or windows, and such landings, doors and windows shall be 
kept clear of ice, snow and other obstructions. Portable seats shall not be 



4 THE SCHOOL HOUSE. 

allowed in the aisles or passageways of such buildings during any service or 
entertainment held therein. If the inspector so directs in writing, women 
or children shall not be employed in a factory, workshop, mercantile or other 
establishment, in a room above the second story from which there is only 
one egress, and all doors and windows in any building which is subject to 
the provisions of this section shall open outwardly, and every room above 
the second story in any such building, in which ten or more persons are 
employed, shall be provided with more than one egress by stairways or by 
such other way or device, approved in writing by the inspector, as the owner 
may elect, on the inside or outside of the building, placed as near as practi- 
cable at each end of the room. The certificate of the inspector shall be 
conclusive evidence of a compliance with such requirements. 

Section 26. Each story above the second story of a building which is 
subject to the provisions of the preceding section shall be supplied with 
means of extinguishing fire, consisting of pails of water or other portable 
apparatus or of a hose attached to a suitable water supply and capable of 
reaching any part of such story; and such appliances shall be kept at all 
times ready for use and in good condition. 

********* 

Section 36. The audience hall in a-building which is erected or designed 
to be used in whole or in part as a theatre or in which any change or altera- 
tion shall be made for the purpose of using it as a theatre shall not be placed 
above the second floor of said building. The audience hall and each gallery 
of every such building shall, respectively, have at least two independent 
exits, as far apart as may be, and if the audience hall is on the second floor, 
the stairways from said floor to the ground floor shall be enclosed with fire- 
proof walls from the basement floor up, and shall have no connection with 
the basement or first floor of the building. Every such exit shall have a 
width of at least twenty inches for every one hundred persons which such 
hall, or gallery from which it leads, is capable of holding; but two or more 
exits of the same aggregate width may be substituted for either of the two 
required exits. None of the required exits shall be less than five feet wide. 

Section 37. The proscenium or curtain opening of all theatres shall 
have a fire resisting curtain of an incombustible material, properly constructed 
and operated by proper mechanism. The certificate of the inspector of 
factories and public buildings shall be conclusive evidence of a compliance 
with such requirements. 

********* 

Section 44 If, in the erection of an iron or steel framed building the 
spaces between the girders or floor beams of any floor are not filled or 
covered by the permanent construction of said floors before another story is 
added to the building, a close plank flooring shall be placed and maintained 
over such spaces, from the time when the beams or girders are placed in 
position until said permanent construction is applied; but openings, pro- 
tected by a strong hand railing not less than four feet high, may be left 
through said floors for the passage of workmen or material. 

Section 45. In the construction of any iron or steel framed building 
having a clear story of twenty-five feet elevation or more, a staging with a 
close plank flooring shall be placed under the whole extent of the beams, 
girders or trusses of such story upon which iron or steel workers are 



THE SCHOOL HOUSE. 5 

working, and not more than ten feet below the under side of such beams 
girders and trusses. 

Section 46. Inspectors of factories and public buildings shall enforce 
the provisions of the two preceding sections, and whoever violates any 
provision thereof shall be punished by a fine of not less than fifty nor more 
than five hundred dollars for each offence. 

Section 51. The supreme judicial court or the superior court shall have 
jurisdiction in equity, upon the petition of an inspector, temporarily o r 
permanently to restrain the erection, construction, use or occupation of a 
building in violation of the provisions of this chapter. 

Section 52. The supreme judicial court or the superior court shall have 
jurisdiction in equity to restrain the illegal placing, maintenance or use of 
any building, structure or other thing. It may, upon the petition of a city 
or town, by its attorney, for such relief, require the removal of any such 
building, structure or other thing by the owner, and may authorize the city 
or town, in default of such removal by the owner, to remove it at his 
expense. The provisions of this section shall apply to such buildings, 
structures or other things so placed which were maintained or used prior to, 
as well as after, the second day of May in the year eighteen hundred and 
ninety-nine. Upon such petition, the defendant shall be presumed to have 
acted without a license or authority until he proves to the contrary. 

Section 53. Sections fifteen to eighteen, inclusive, twenty-two to twenty- 
six, inclusive, thirty, thirty-one, thirty-six, thirty-seven, forty-eight to fifty- 
one, inclusive, and fifty-four shall not apply to the city of Boston. 

Section 5-1. Cities may by ordinance provide that the provisions of 
sections fifteen to eighteen, inclusive, twenty -two to twenty-six, inclusive, 
thirty-six, thirty-seven, forty-eight and forty-nine shall apply to any building 
of three or more stories in height within their respective limits. 

Section 55. Whoever, being the owner, lessee or occupant of any 
building or room described in section twenty-two violates the provisions of 
sections fifteen to eighteen, inclusive, twenty-two to twenty-six, inclusive, 
thirty-six, thirty-seven, forty-eight and forty-nine, shall be punished by a 
fine of not less than fifty nor more than one thousand dollars. 

Section 5(5. Whoever violates any provision of this chapter for Avhich 
no other penalty is specifically prescribed shall be punished by a fine of not 
more than one hundred dollars. 

Chapter 106, Revised La-ws, Massachusetts. 

Sanitary Provisions. 
********* 

Section 54. Every public building and every school house shall be kept 
clean and free from effluvia arising from any drain, privy or nuisance, shall 
be provided with a sufficient number of proper water closets, earth closets, 
or privies, and shall be ventilated in such a manner that the air shall not 
become so impure as to be injurious to health. The provisions of this 
section shall be enforced by the inspection department of the district police. 

Section 55. If it appears to an inspector of factories and public buildings 
that further or different sanitary or ventilating provisions which can be pro" 



6 THE SCHOOL HOUSE. 

vided without unreasonable expense, are required in any public building or 
school house, he may issue a written order to the proper person or authority, 
directing such sanitary or ventilating provisions to be provided. A school 
committee, public officer or person who has charge of, owns or leases any 
such public building or school house who neglects for four weeks to comply 
with the order of such inspector shall be punished by a fine of not more than 
one hundred dollars. Whoever is aggrieved by the order of an inspector 
issued as above provided and relating to a public building or school house 
may, within thirty days after the date of the service thereof, apply in writing 
to the board of health of the city or town to set aside or amend the order ; 
and thereupon, the board, after notice to all parties interested, shall give a 
hearing upon such order, and may alter, annul or affirm it. 



After the committee have decided upon the plan preferred, they 
can then report to the city or town and ask for an appropriation 
sufficient to properly construct the building. 

The appropriation should be sufficient to cover the entire cost of 
the site, building, furnishing, grading and the architect's fee, also 
a reasonable allowance for contingencies. By this method addi- 
tional appropriations are avoided, and the committee and architect 
are not obliged to revise the plans and omit essential things in 
order to keep within the appropriation. 

The appropriation having been made, the committee should be 
authorized to contract for the building. 

If architects, before making the finished drawings, or committees, 
before accepting them, would (in Massachusetts) submit them to 
the State Inspector for the district, the inspector will inform them 
as to whether or not the plans meet the requirements of law and 
will be approved. 

Sometimes a committee will accept plans that the inspector can- 
not approve, and changes will be ordered which may increase the 
cost after the appropriation is made, or will allow the contractor to 
present a bill for " extras." " Be sure you are right and then go 
ahead." 

In deciding upon competitive plans committees are often pleased 
with a well-drawn and colored elevation or perspective, and some- 
times lose sight of the more important interior arrangement of the 
rooms, etc. 

Site. 

In deciding upon the choice of a site for a schoolhouse many 
different questions will arise : as to where it should be located to 
be near the central part of the district, the cost of the land, the 
nature of the soil, and the objectionable surroundings to be avoided. 



THE SCHOOL HOUSE. 7 

F A site on high, dry land where a good foundation and good 
drainage or sewerage can be had should be selected if possible. 

If low or filled land must be used, care should be taken that good 
foundations are provided and supported by well-driven piling, if 
necessary ; also that the walls and bottom of the basement are well 
protected and made water-tight by asphalt or hydraulic cement. 

If the schoolhouse is to be built on clav or on land containing 
springs of water, proper precautions should be taken to provide 
suitable drainage by a trench outside, filled with small stones, or 
by drain-tile placed outside to carry off the water. 

When any doubt exists as to the nature of die ground it is advis- 
able that borings be made to determine whether there are quick- 
sands, springs, or unstable places, also as to whether ledges are to 
be found in excavating. By doing this the architect and con- 
tractors will be enabled to make a better estimate of the cost, and 
bills for " extras " are often avoided. 

A site should be selected where a good light can be had on all 
sides of the building, and unobstructed by trees or high buildings. 
High buildings or trees close to a schoolhouse often prove serious ob- 
stacles to good ventilation on account of deflection of the wind, which 
sometimes causes reversed drafts in chimneys and ventilating flues. 

It is not desirable to place the schoolhouse where it is much 
exposed to very high winds. 

The building should be set well back from the street and ample 
yard room provided. 

Close proximity to manufacturing establishments, where much 
smoke or noxious gases are produced, should be carefully avoided, 
as well as a noisy location, where pupils and teachers are annoyed 
and their attention diverted from school work. 

The Building. 

School buildings should be plain, and substantially built. 

The money frequently expended in the construction of towers, 
cupolas, and other ornamentation, can be used to much better 
advantage in substantial construction and convenient interior 
arrangements. 

Not that a building should be hideously plain ; but a well 
proportioned building, with simple and inexpensive ornamentation, 
can easily be designed by an experienced architect. 

A schoolhouse, two stories in height, and, in large buildings, 
with an assembly hall above the second story, is to be preferred to 
one of three or four stories. 



8 THE SCHOOL HOUSE. 

In case of fire or panic the danger is greatly increased in high 
buildings. 

Climbing many nights of stairs, especially for girls, is not 
recommended. 

In cities where land is very valuable it sometimes becomes 
necessary to have the school building more than two stories high ; 
but where land can be obtained at a reasonable price two stories 
are preferable. 

Construction. 

When a sufficient appropriation can be obtained it is preferable 
that the building be of fire-proof, or at least, slow-burning 
construction. 

After the first cost the expenditure for repairs is much less for 
brick than for "wooden buildings. 

If wooden construction is adopted on account of the first cost, 
care should be taken that the material is of good quality, the 
timber of sufficient size, and the boarding well protected with a 
covering of the best quality of building paper. 

A loosely-constructed building requires in cold weather a 
constant additional expenditure for fuel to maintain a comfortable 
temperature in the schoolrooms. This additional expense can be 
considerably reduced by good construction in the first place. 

Particular attention should be given to have all trusses properly 
designed, placed, and of sufficient strength. 

The writer has found more well-founded complaints of insuffi- 
cient trussing and defective roof-framing than from any other 
cause (exclusive of heating and ventilation) in schoolhouse 
construction. 

It is too often the case that architects are obliged to cut down 
the thickness of walls and partitions and reduce the size and 
quality of the timber because a building committee insists on 
having a large building for little money. This is false economy, 
as will be apparent after the building is occupied. Better reduce 
the size of the building than cut down the material. 

In brick schoolhouses an air space in the walls is advisable, and 
the inner walls should be of hard-burned brick with terra-cotta set 
to receive nailing for the finish. 

The wood finish should be reduced to the minimum, and the 
walls smooth plastered. 

In the better class of buildings Windsor or equally good cement 
can be advantageously used for door and window trims. Dados of 
gauged mortar and wood base are also used. 



THE SCHOOL HOUSE. 9 

Oak or ash finish is preferable to white pine or whitewood, 
which are too soft and easily defaced. Cypress is sometimes used, 
and in the cheapest buildings Southern pine is frequently used. 

Expanded metal is much better than wooden lathing. Stamped 
metal ceilings are sometimes used, but the advantage is not great 
when the extra cost is taken into account. 

In some cases in brick school buildings the wood finish in the 
corridors is omitted and faced brick, carefully laid, and painted 
with a light-colored gloss paint, is substituted. This has proved 
quite satisfactory. 

The upper floor-boards should be of rift Georgia or Florida pine, 
or of maple, and not over four inches wide. Between the upper 
and lower floor-boarding should be laid asbestos or other fire 
resisting paper or material. 

Means to Prevent Spread of Fire. 

The following are the requirements of the Massachusetts State 
Inspectors for buildings other than in the city of Boston : 

General Specifications for Means of preventing Spread op Fire in Buildings, 
under the Requirements of Chapter 104 of the Revised Lazvs, as directed 
by the State Inspectors of Factories and Public Buildings. Special Provi- 
sions against Spread of Fire, required in Theatres, are not included in 
those Specif cations. 

1. All elevator wells and light shafts, unless built of brick, must be filled 
in flush between the wooden studs with fire-proof materials and lined with 
metal or plastered on metallic lathing, as may be directed by the inspector, 
and all wood-work inside of such wells or shafts, be lined with tin plate, 
lock-jointed. 

2. Where floor beams rest on partition caps or on girders, wall girts, or 
on wooden sills, fill in between such beams, from the caps, girders, girts or 
sills, to four inchesabove the plaster ground solid with brick and mortar or 
other fire-proof material. 

3. When floor beams in frame buildings rest on ledger boards, fire-stop 
thoroughly at each floor with brick and mortar resting on bridging pieces cut 
in between the studs, or, where practicable, on the ends of lining floor. 

4. In brick buildings the space between the furrings on the outside walls 
or on brick partitions should be filled flush with mortar for a space of five 
inches in width above and below the floor beams of each story. 

5. Where basement or other flights of stairs are enclosed by partitions of 
brick or wood, the spaces between the studs or wall furrings must be so fire- 
stopped with brick or mortar as to effectually prevent any fire from passing 
up between such studs or furrings back of the stair stringers. 

6. The soffits of all such enclosed stairs, and also partitions on stairway 
side, must be plastered on metal lathing. 

7. Where a building is occupied above the first floor for any purpose 
which renders it subject to the provisions of section 22 of chapter 104 of the 



10 THE SCHOOL HOUSE. 

Revised Laws, and the lower story is occupied for stores, or other purposes 
not connected with the upper floors, the stairways leading to such upper 
floors must be enclosed with brick walls or with wooden partitions filled 
solid with brick laid in mortar, or other fire-proof material, and plastered on 
both sides on metallic lathing, and all doors in such partitions lined with tin 
plate, lock-jointed. 

8. All long flights of stairs to have smoke-stops in each flight, properly 
constructed. 

9. No pipes for conveying hot air or steam can under the law be placed 
nearer than one inch to any wood-work unless protected to the satisfaction 
of the inspector by suitable guards or casings of incombustible material. 

10. No wooden flue or air-duct of any description can be used for heating 
or ventilating purposes. 

11. A space of at least one inch to be left between all wood-work and the 
chimneys, also around all hot-air, steam and hot-water pipes ; these spaces 
around chimneys and pipes, where they pass through floors, to be stopped 
with metal or other fire-proof material, smoke-tight. Steam and hot-water 
pipes to have metal sleeves and collars. 

All channels and pockets for gas, water and soil-pipes to be made smoke- 
tight at each floor. 

12. The space around all metal or brick ventilating ducts must be fire- 
stopped at each floor with metal or other fire-proof material, as approved by 
the inspector. 

13. All chimneys to be plastered with one good coat of brown mortar, on 
the outside .of brick-work, from cellars to roof. 

14. The ceiling of furnace or boiler and indirect radiator rooms must be 
plastered on metal lathing. There should be not less than one foot in height 
of open air space between the tops of furnace or boiler casing or any smoke- 
pipe and the ceiling. 

15. The entire cellar ceilings of schoolhouses and other buildings used 
for public purposes mu'st be plastered on metallic lathing. 

So much of these specifications as applies to any building should be incor- 
porated by the architect in his specifications for said building, and the clauses 
therein incorporated should be indicated by their numbers in the specification 
filed with the inspector. 

These specifications are to be followed in every building subject to the 
provisions of section 22 of chapter 104 of the Revised Laws, unless omitted 
or changed in some part by special consent of the inspector. 

Other provisions than those herein specified, to prevent spread of fire, may 
be required by the inspector if deemed by him to be necessary. 

Means to Extinguish Fire. 

Chapter 104 of the Revised Laws of Massachusetts requires that 
means to extinguish fire be provided in certain buildings, as fol- 
lows : 

Section 25. A building which is used, in whole or in part, as a public 
building, public or private institution, school house, church, theatre, public 
hall, place of assemblage or place of public resort, 



THE SCHOOL HOUSE. 11 

Section 26. Each story above the second story of a building which is 
subject to the provisions of the preceding section shall be supplied with 
means of extinguishing fire, consisting of pails of water or other portable 
apparatus or of a hose attached to a suitable water supply and capable of 
reaching any part of such story ; and such appliances shall be kept at all 
times read}' for use and in good condition. 

Although not required by the Massachusetts laws, it is advisable 
that each story, including the basement, should be provided with a 
chemical fire-extinguisher, or a stand-pipe and hose not less than 
two inches in diameter. Suitable and neat hose racks should also 
be provided in the corridors. 

In order that the stand-pipe may be tested to see if it is full of 
water, and to do this without wetting the hose, it is advisable to 
place in the stand-pipe, just below the valve in each story, a small 
try-cock. Care should be taken that the connection with the 
street water main is not less in diameter than that of the stand- 
pipe in the building. 

Basement. 

The basement should not be less than ten feet high and twelve 
feet is preferable. 

It should be well lighted, and when practicable, at least five 
feet should be above ground. 

The basement floor should be of concrete, not less than four 
inches thick, with a well-smoothed covering of three-quarters of 
an inch thick of rock asphalt or Portland cement. Rosendale or 
similar cement is unsuitable for the top covering of a schoolhouse 
basement on account of being easily worn and broken by the 
pupils. When so used there is complaint of the dust arising from 
the fine detached particles of cement. 

On wet, filled or clayey ground it is advisable to cover the 
outside of the foundation and bottom of the basement concrete 
floor with boiled asphalt to prevent moisture or earth exhalations 
from entering the building. 

The floor of the boiler, furnace and coal rooms should be paved 
with brick, preferably set on edge in cement mortar. 

The floor of the sanitary and playrooms should be graded to 
some convenient point, at which a drain with a perforated cover is 
placed, in order that the floor may be thoroughly washed by water 
from a hose. 

The drain for this purpose should be well trapped and not 
connected with the drain from the sanitary fixtures. 

The heating apparatus, cold-air rooms, sanitary, play and lunch- 



12 THE SCHOOL HOUSE. 

rooms should be in the basement, and when a manual training room 
or gymnasium is there, the wood floor should be laid on screeds 
embedded in concrete, and the space between the screeds filled 
with cement or cinder concrete. 

A chemical laboratory should never be placed in the basement. 

The flooring of the rooms over the cold-air room should be well 
protected by some non-conducting material to prevent the cold 
from striking up through the floor of the first story. 

This is sometimes done at a moderate expense by fastening two 
or more thicknesses of building or thick asbestos paper between 
the floor timbers, about half-way between the metallic lathing and 
the floor boarding, holding it in place by strips of furring nailed to 
the sides of the floor-beams. 

A bicycle run and stalls or racks should also be provided. 

Galvanized iron ash-holders should be provided for removing 
the ashes from the boiler or furnace room, also a convenient ash- 
lift or door. 

Suitable soapstone or iron sinks, drinking-cups and wash-basins 
should be provided in the play-rooms ; also in the boiler or furnace- 
room for the use of the janitor or engineer. 

Where practicable, a janitor's room and work -bench should be 
provided. 

Hose and pipe should also be provided for washing. 

Danger from fire is greater in the basement than in other parts 
of the building, and as little wood finish should be used there 
as possible. 

It is advisable that the boiler or furnace rooms should be fire- 
proof ; or, at least, of slow burning construction, and that metal- 
covered doors be used for these rooms. 

The basement stairways should be shut off from the corridors by 
doors to prevent smoke from rapidly filling the corridors and 
upper stairways. 

Closets should not be allowed under stairways, as they frequently 

become receptacles for inflammable material, such as waste paper, 

oil-cans, etc. 

Corridors. 

Corridors should be wide and well lighted. Twelve feet is not 
too wide, and when the outer garments of the pupils are hung 
there fifteen feet is to be preferred. 

In small schoolhouses the outer garments can be hung there, 
either on wall supports, or in stalls preferably made of wire grill 
work of about one-eighth inch diameter wire, and about two inches 



THE SCHOOL HOUSE. 13 

diamond mesh. This gives a much better chance for the air to 
circulate than when wood partitions are used, and the pupils, when 
the wire grill work is used, can be kept in view of the teachers. 
The top of the grill work is usually from five to six feet, and the 
bottom about one foot above the floor. 

A shelf of wire grill, on which to place overshoes, is often put 
at the bottom of the upright grill. In some cases another shelf is 
placed near the top. Hat and coat hooks in primary schools are 
placed four feet above the floor, and in other schools five feet. 
Thirty running feet for a fifty seat room is usually the minimum 
hanging space. 

It is advisable to run two lines of one and one-quarter inch 
steampipe a short distance above the floor and under the clothing, 
for the purpose of drying in stormy weather. 

Where practicable, umbrella racks are advisable. 

All corridors and clothing rooms should be well ventilated ; but 
it is not requisite that a separate air supply should be provided, as 
the leakage of outside air and the frequent opening of outside doors 
will generally furnish the required amount of fresh air. A good 
exhaust duct is, however, necessary. 

" Foot- warmers " should be in all cases provided in the lower 
corridor, in order that in cold or stormy weather the pupils may be 
provided with means for drying and warming their clothing and 
feet. The air supply for the foot warmers may be taken in through 
the risers in the vestibule stairs, or it may be rotated from the 
corridor. 

In large buildings, or where the cost does not prevent, separate 
coat rooms may be provided. 

E. M. Wheelwright, in his excellent work on schoolhouse archi- 
tecture, says, " specially designed separate clothing rooms add 
about from four to four and one-half per cent to the cost of the 
building." 

A hand bowl and faucet or drinking fountain should be provided 
in each corridor, and in some cases a mirror, soap and towels are 
added. 

Glass panels in the class-room doors assist materially in lighting 
the corridors and enable the teachers to observe what is passing 
there. Transoms over the doors are also desirable. 

In some buildings, where long and difficultly lighted corridors 
are designed, small windows near the ceiling of the class-rooms 
have been used to good advantage to assist in lighting the corridors. 



14 THE SCHOOL HOUSE. 

Vestibules. 

Vestibules are desirable for all schoolhouses. They should be 
well lighted and have self-closing doors. 

In cold and stormy weather, where no vestibules are provided 
the corridors and other parts of the building are often very rapidly 
cooled, especially before the session or during recess, by opening 
outside doors directly into the corridor. 

In the matter of economy of fuel, if for no other reason, vesti- 
bules should always be provided in schoolhouses. 

If it is not practicable to construct a vestibule, a temporary out- 
side storm porch should be constructed of matched boards for use 
in winter, and capable of being removed for warm weather. 

Exits. 

There should be at least two ways of exit from every 
schoolhouse. 

The stairways and outside doors' should be placed as far apart as 
practicable and should be not less than four feet wide. Five feet 
is better. 

The Massachusetts inspectors require means of exit equal to 
twenty inches for each one hundred persons accommodated in a 
public building ; but no stairway to be less than four feet wide 
in the clear. (For theaters the law requires forty inches for each 
ipo persons, and no exit to be less than five feet wide.) 

When the expense can be incurred it is desirable that stairways 
in brick school-buildings be made fire-proof and enclosed in brick 
walls. The stairs should be of iron, and in the treads should be 
embedded safety treads, not less than five and one-malf inches 
wide, and made of a combination of steel and soft metal, or 
rubber covering can be advantageously used. 

In wooden buildings the sides of the stair-stringers should have 
the spaces between the studs or wall-furrings so stopped with 
brick or mortar as to effectually prevent fire from passing up 
between the studs or furrings back of the stair-stringers, and the 
soffits of enclosed stairs, and the partitions on the stairway-side 
should be plastered on expanded metal lathing. At least two 
cut-offs or fire stops should be put in each stairway. 

Enclosed stairways should have a substantial hand-rail on each side. 

Open stairways should have a hand-rail on the wall side, and 
especial care should be taken that the outer posts and balusters are 
strong enough to prevent being broken or pushed out of place 
should the stairway become overcrowded in case of panic. 



THE SCHOOL HOUSE. 15 

Circular stairways or winders should never be placed in school- 
houses or places of assemblage. 

In the lower grade schools, risers should preferably be six inches 
with twelve-inch tread ; in other grades, risers not more than seven 
inches, with ten and one-half inches tread. 

The product of the rise and run should not be less than seventy 
or more than seventy-five. 

There should not be less than two, nor more than fifteen steps 
between landings, and landings not less than four feet long. 

The ordinary fire-escape, such as is used on factories, hotels, 
tenement-houses, etc., should never be placed on a school-buildi?ig 
unless it is impossible to provide other -ways of exit. 

The danger would be very great if in case of fire an attempt 
should be made to have a large number of children go down the 
narrow fire-escapes of the ordinary design. 

The pupils would be very likely to become frightened when they 
looked down from the open fire-escape, would hesitate, stop, and 
be pushed by those in the rear, and a panic would ensue. 

The writer has not for many years required the ordinary fire- 
escape to be placed on any schoolhouse. When additional means 
of exit from a schoolhouse must be provided, it should be by 
enclosed stairways with hand-rails on each side. 

Outside main entrance and vestibule doors should open out or 
both ways. 

The standing leaf of all pairs of doors leading to ways of egress 
should be fastened by face T-bolts, operated at top and bottom by 
one handle placed at a convenient height from the floor. 

Edge bolts should not be used, on account of the difficulty of 
opening quickly. 

Schoolhouse doors should never be fastened during school hours 
in a manner that will prevent them being quickly opened from the 
inside. If desirable to prevent persons from entering the building, 
the door-knobs may be arranged to open the door from the inside, 
but not from the outside. An electric bell should be provided for 
the use of persons desiring to enter. 

Doors used as exits from the building should be at least equal in 
width to the stairways. 

No door opening inward at the bottom of any stairway should be 
allowed in any public building. 

Door-checks for outside doors will soon save the additional cost 
in the amount of fuel burned in cold weather. 



16 THE SCHOOL HOUSE. 

From each class-room at least one door should open out, and 
class-rooms on the same story or side of the corridor should have 
connecting doors. 

Windows. 

Windows in class-rooms should preferably be four feet between 
jambs, three feet above the floor, and about six inches, or only 
enough for the finish, from the top to the ceiling. 

Four lights of glass in each window is a desirable number. 

Three windows at the rear and four at the left of the pupils give 
a very good light for the ordinary sized school-room, lighted from 
two sides. 

When only lighted from the left of the pupils' desks, five 
windows are preferable if the construction of the building will 
allow it. 

Arched windows are objectionable in a class-room. 

Transoms may be allowed for summer ventilation where a gravity 
system is used ; but double windows are more desirable, especially 
on the sides most exposed to the prevailing winter winds. A very 
considerable saving of fuel is made by their use, and they also to a 
large extent prevent the cold drafts caused by the rapid cooling of 
the air on the glass surface. 

Double-glazed sash, that is, two lights of glass set with about 
one-half-inch air space between them, is sometimes used to good 
advantage, but is not as desirable as double run of sash. 

When double glazing is used care should be taken that the glass 
is thoroughly cleaned and dried before setting. 

When either the gravity or mechanical system of ventilation is 
in use all windows, transoms and doors in class-rooms should be 
closed in order to obtain the best results. 

Windows should have an eye or a depressed piece of metal set 
into the upper part of the sash, by means of which they can be 
easily lowered or raised with a window pole or rod. 

Transoms should be hung at the bottom and opened or closed by 
adjusting rods. 

Class-room doors opening into a corridor should have a large 
light of heavy glass set in the center and about four feet above the 
floor. 

Windows grouped as mullions do not give as satisfactory light 
as when equally spaced in the outer wall. 

Basement windows should when practicable be about four feet 
high and correspond in width to those in the stories above. 



THE SCHOOL HOUSE. 17 

Care should be exercised that all spaces about the window frames 
are caulked or made as tight as possible. Neglect of this precau- 
tion is often a cause of complaint of uncomfortable drafts. 

Venetian or other blinds are very objectionable in school rooms. 

Roller shade curtains, which can be adjusted to raise or lower 
from either the top or bottom, by means of a slide or a rod at each 
side of the window, and operated by a cord to hold the curtain in 
any position, are very desirable, and enable the teacher to regulate 
the light in a satisfactory manner. 

Many of the modern school buildings are now provided with 
these adjustable curtains. 

They assist in partly solving the much-discussed problem of using 
light from the north or other points of the compass. 

Much has been written regarding the amount of light admitted 
to a schoolroom, and from which point of the compass it should 
come. 

To carry out the theories of some writers would require the class- 
rooms to be of a height that would very materially increase the cost 
of the building. 

By having a sufficient number of wide windows which extend 
nearly to the ceiling, and by the judicious use of properly colored 
adjustable curtains, many of the objections can be in a great 
measure overcome. 

The theory that only a north light should be used in a school- 
room will often lead to objectionable conditions in the heating and 
ventilation. 

Where a corridor is located north or northwest from class-rooms 

a more even temperature and better circulation of air is obtained 

than where the class-rooms are exposed to the prevailing winds, 

which in Massachusetts are from the northwest and north in the 

winter. 

Class-Rooms. 

The standard generally adopted for a class-room in Massachu- 
setts, for what is usually called a fifty seat room, is 32 feet long, 
28 feet wide and 12 feet high. 

In the lower grades sometimes 56 seats are provided, but this 
large number is not recommended. 

Grammar and the high grade rooms are commonly seated for 
42, 47, 48 or 49 pupils. 

Twenty-eight by thirty-two feet gives a floor space of 896 square 
feet, and allows 21.33 square feet of floor space for 42, 19.06 for 
47, 18.66 for 48, and 18.28 for 49 pupils. Allowing one teacher 



18 THE SCHOOL HOUSE. 

per room gives respectively 20.83, 18.16, 18.28 and 17.92 square 
feet of floor space for each occupant. 

The rooms being 12 feet high gives 10,752 cubic feet of air 
space. This space includes that occupied by the furniture and 
persons in the room. Usually this is not taken into consideration, 
but for accurate calculation it should be. 

Allowing 42, 47, 48 and 49 pupils, this 10,752 cubic feet of air 
space gives respectively 256, 228.7, 224 and 219.42 per pupil, or, 
allowing for one teacher, we have 250.04, 224, 219.42 and 215.44 
cubic feet of air space per person. 

For approximate calculation we may estimate an ordinary school- 
room in Massachusetts as containing 10,000 cubic feet of air space. 

While these amounts of floor and air space do not quite agree 
with the recommendations of a number of writers, yet with a • 
properly designed system of heating and ventilation 30, 40 or 50 
cubic feet of air per minute may be supplied to each occupant with- 
out uncomfortable drafts being perceived. 

With wide and high windows, properly located, very little com- 
plaint can reasonably be made as to satisfactory lighting. At least 
this has been the experience of the writer while making many tests 
of heating and ventilation, and in many conversations with teachers 
and pupils. 

Twelve feet appears to be a desirable height for ordinary class- 
rooms where the inlets and outlets for ventilation are of ample size 
and properly located. 

This height will allow a good circulation of air, while a lower 
stud may sometimes cause uncomfortable drafts. A higher stud 
than 12 feet increases the cost of the building without giving an 
adequate return. 

In rooms 14 feet high the circulation of air is no better than in 
those 12 feet high. 

Skating. 

The convenient arrangement of seats in a class-room will depend 
upon the number of pupils to be accommodated. 

In assembly and public halls (except theaters) the Massachusetts 
inspectors allow six square feet of floor space for each person. 
This includes aisles, and the open spaces hi front of the stage or 
platform and at the rear of the seats. 

In determining the width of exits from halls or places of assem- 
blage, divide the number of square feet of floor space in front of the 
stage or platform by six for the seating capacity. The width of the 



THE SCHOOL HOUSE. 19 

exits is determined by the seating capacity ; allowing 20 inches for 
each 100 persons; but no exit to be less than four feet wide. 

It is intended that the audience shall pass out in lines 20 inches 
wide ; that is, 200 persons should have at least forty-eight inches 
in width of exit; 300, sixty inches ; 400, eighty inches, etc. 

Lecture-rooms in the larger schoolhouses are generally seated in 
amphitheatre form, and seats with a broad arm or small table- 
attachment are desirable to enable the pupils to conveniently make 
notes of the lecture. 

In class-rooms the seats should be arranged in a manner that 
will allow the light to reach the pupils from the left and rear when 
the room is lighted on two sides, and from the left when the light 
is from one side only. 

When the light comes from the right the effect is bad, especially 
when the pupils are writing, the shadow of the hand being very 
trying to the eyes. 

Class-room seats should never be placed in a position which 
requires the pupils to face the windows. The teacher, not being 
obliged to remain in one position, can better face the light occa- 
sionally than to require all the pupils to do so constantly. 

In most modern schoolhouses the teacher's platform is omitted, 
and a movable desk which can be placed in any desirable position 
is provided. 

The ordinary size for a teacher's desk is about 50 inches long, 
30 inches wide, and 31 inches high. 

Seats and desks, the height of which can be adjusted to the size 
of the pupils, are much better than those which require pupils of 
different ages and height to have the same size desk and seat. 

There are several styles of adjustable seats and desks in the 
market, and money expended in this manner is well invested for 
the health and comfort of the pupils. 

The seats and desks should be adjusted to the size of the pupils 
at least as often as the beginning of each school term. 

The old-fashioned double seats and desks occupied by two pupils 
should not be tolerated in any modern class-room. Seats and desks 
in class-rooms should be adjustable in order that they may be fitted 
to the needs of each individual pupil. 

Ill-fitting seats and desks are often responsible for round 
shoulders, spinal curvature, and impaired eyesight. 

There are measuring gauges by means of which the height of 
seats and desks may be readily adjusted. 



20 



THE SCHOOL HOUSE. 



The following show samples of adjustable and other kinds of 
furniture used in Massachusetts schoolhouses. 




Fig 1. 



Fig. 2. 




Fig. 3. 



Fig. 4. 



Tablet 
Arm 




Fig. 5. 



Figs. 6 and 7. 



Fig. 8. 



THE SCHOOL HOUSE. 



21 



Side aisles are usually from three to four feet wide. Aisles 
between desks are usually 18 inches, but vary from 16 to 24 inches, 
according to size of the room and the number and 
size of desks. 

In high schools the distance between rows of 
desks is often 30 inches, and the desk tops are 20 
by 26 inches. 

In schoolhouses having a room for the principal 
or head master there will generally be found a 
roller-top desk for his use, and frequently a lounge 
and extra chairs are provided. 
A carpet and some appropriate pictures add to the general 
appearance of the room. 

The following sizes may be considered as desirable for pupils of 
different ages and grades. 




Fig. 9. 



Ages. 



5 or 6 years 

6 or 7 years 

7 or 8 years 

8 or 9 years 

9 or 10 years 

10 or 11 years 

11 or 12 years 

12 or 13 years 

13 or 14 years 



Grades. 



Dimensions 

of Desk Top 

in Inches 



12 x 18 

13 x21 

16 x24 

18 x24 
20 x 26 



Range of Height of Adjustment in Inches. 



Chair. 



91 to 13* 
10| to 15 

12$ to 17 



131 to 181 



Desk. 



17J to 224 
18 to 25 

204 to 29 



23 to 31 



Age of Pupil. 



4 to 8 years 

5 to 12^ears 

7 and upwards 



11 and upwards 



High-school desks are usually made with tops either 18 x 24 
inches or 20 x 26 inches. 



Dimensions of 
Desk Top. 


Space Occupied. 


12 x 18 inches 


1 


From side to side, 18 inches 

From front of desk to rear of chair, 


25 inches 


13 x 21 inches 


{ 


From side to side, 21 inches 




From front of desk to rear of chair, 


27 inches 


16 x 24 inches 


{ 


From side to side, 24 inches 




Front front of desk to rear of chair, 


30 inches 


18 x 24 inches 


1 


From side to side, 24 inches 




) 


From front of desk to rear of chair, 


34 inches 


20 x 26 inches 


{ 


From side to side. 26 inches 




From front of desk to rear of chair, 


36 inches 



Allow one inch between back of desk and back of chair. 



22 THE SCHOOL HOUSE. 

Blackboards. 

Class-room blackboards should be of slate and set on the two 
inner walls. Where an appropriation will allow, all available 
space should be so occupied. Not that the space between the 
windows should be used for daily exercises ; but exhibition draw- 
ings or artistic designs drawn there add much to the general 
appearance of the room. 

Blackboards should be at least 3 feet high ; 3 feet 6 inches or 
even 4 feet is not excessive in the higher grade rooms. 

In primary schools they are set 2 feet 4 inches, and the other 
grades 3 feet above the floor. 

A chalk and eraser receiver 2^ inches wide should be set below 
the blackboard. 

In lecture-rooms sliding blackboards set in frames that will allow 
two or more boards to be used in succession are advisable. 

Clocks, Thermometers and Pictures. 

A clock should be provided in each class-room. In many of 
the larger buildings electric clocks connected with a regulating one 
in the head master's room are provided in the several class-rooms, 
and indicate the time for various recitations or change of classes. 

A thermometer should also be placed in each class or recitation 
room, and if proper attention is given to the indicated temperature 
more satisfactory results will be obtained, not only as to the com- 
fort of the teacher and pupils, but a considerable saving can be 
made in fuel. 

It is advisable to place the thermometer about on the breathing 
line of the pupils when in their seats, and to hang it in a location 
where it will be but little acted on by the rays of the sun, or by 
cold outside walls or drafts from windows or doors, or opposite a 
warm-air inlet. 

On the teacher's desk or on an inside wall is generally the best 
location. 

At least one thermometer should be placed on the outside of the 
building in such a position as will screen it as much as possible 
from the direct rays of the sun. This will be of service to the 
janitor in regulating his fires, and thereby controlling to a consid- 
erable extent the amount of fuel used. 

Moulding for hanging pictures is often provided in schoolrooms 
and a few appropriate pictures add much to the general appearance 
of the room. 



THE SCHOOL HOUSE. 23 

In many of the large school buildings appropriate plaster casts 
are provided, which with artistic pictures in various parts of the 
building present a fine appearance and are appreciated by teachers, 
pupils and visitors. 

In many of the large school buildings provision is often made 
for additional rooms : for an assembly hall, manual training, 
gymnasium, chemical, physical and biological laboratories, type- 
writing and stenography, business course, cooking, lunch, teachers, 
clothing, sanitary, emergency, library, and a janitor's workroom ; 
also book cases and storage closets. 

In many schoolhouses, telephone connection is provided between 
the class-rooms and for the janitor and the principal's room. This 
is more desirable than speaking tubes, which are, however, used 
to a considerable extent. 

In many buildings telephone connection is provided through the 
'* central " telephone office with other buildings and with the 
superintendent of schools. 

Fire-alarm boxes are often placed in or near schoolhouses for 
use in case of emergency. 



' CHAPTER II. 



AIR. 

THE atmospheric air we breathe consists of a mechanical 
mixture of approximately 21 parts of oxygen and 79 
parts of nitrogen, and usually about four parts of carbonic 
acid in 10,000 parts of air. 

A large number of analyses taken in different places by different 
persons show that when the air is not particularly contaminated by 
local conditions four parts of carbonic acid gas in 10,000 parts of 
air may be considered a fair standard. 

A number of other substances are also found in air, such as ozone, 
watery vapor and organic matter given off by living animals, dust 
particles, microbes, ammonia compounds, sulphuretted hydrogen, 
sulphurous and sulphuric acid, nitrous and nitric acid, carbonic 
oxide, sewer gas and many substances produced by various sources 
of contamination ; also some 30 species of moulds and yeasts, 
together with the recently discovered argon and other substances. 

In breathing, the movements of respiration follow each other at 
the rate of 18 or 20 a minute. 

Quetelet gives the respirations per minute at : 

Birth, 44 ; five years, 26 ; from 15 to 20 years, 20 ; from 20 to 
25 years, ,18. 7 ; from 25 to 30 years, 16 ; from 30 to 50 years, 18.1. 

Dr. Edward Smith found from numerous experiments that the 
average depth of respiration was 33.6 cubic inches' when at rest. 

Different authorities give the amount of air inspired and expired 
as from 26 to 40 cubic inches. The movements of respiration are 
accelerated by muscular action. 

When the lungs have been emptied by expiratory effort they still 
contain in the smaller bronchi and air sacs a quantity termed 
residual air, which cannot be expelled, and which is estimated by 
different authorities as from 40 to 100 cubic inches. A fair average 
may be taken as 75 cubic inches. 

Allowing the amount of air inspired and expired to be 30 cubic 
inches at each respiration, and 20 respirations per minute, makes 600 
cubic inches of air, or .34 cubic feet of air actually used per minute. 

The air inhaled passes through the lungs and is deprived of a 
percentage of its oxygen, which passes into the blood, where it is 



THE SCHOOL HOUSE. 25 

taken up by the tissues, which are oxidized and carbonic acid gas 
and other impurities are taken away by the expired air, which, on 
leaving the lungs, contains about 400 parts of carbonic acid instead 
of the four parts in 10,000 parts of air when inhaled. 

Oxygen is the life-giving element of the atmosphere and is 
essential for the support of life and also combustion. 

In the human body there are constantly going on chemical 
changes which may be compared to the action of a fire, Acting 
upon the excess of carbon and other ingredients in the blood, 
chemical compounds are formed and thrown off by the breath of 
the individual. Thus the life-giving element of the air is reduced, 
and poisonous and harmful substances arc introduced in its place. 

The nitrogen is practically inert in the process of respiration and 
combustion, and is not affected by passing through the lungs or a 
fire. It renders the oxygen less active and absorbs some of the 
heat produced. 

Carbonic dioxide (C0 2 ), or carbonic acid, is the result of 
combustion of carbon, and although not in itself considered a 
poisonous gas, yet it may cause the death of a person by suffocation 
for want of the life-giving oxygen. 

As a product of respiration and combustion, carbonic acid is 
taken as an indication of the amount of other impurities present, 
and should not exceed eight parts in 10,000 in air intended for 
breathing, and in many well-ventilated buildings it is often found 
less than six parts. 

Carbonic oxide (CO) is distinctly a poison, and has a character- 
istic reaction on the blood. Carbonic oxide is doubly dangerous, 
for, like carbonic acid it is devoid of smell. 

Persons narcotized with carbonic acid may be restored to life and 
health by prompt removal to the fresh air, or by artificial respiration. 

Poisoning with carbonic oxide is a much more serious matter, 
and admitting fresh air, or even pure oxygen gas, is often power- 
less to overcome the poison of carbonic oxide. 

When the draft in a furnace or heater is insufficient the combus- 
tion is only partly complete, full oxidation of the carbon of the fuel 
does not take place, and carbonic oxide is formed. 

The escape of this gas into a room should be carefully guarded 
against. Especial care should be taken that there are no open 
joints or cracks in the furnace or heater. 

Organic nitrogenous substances exhaled with air from the lungs 
are poisonous, and their presence may be noted in the stagnant, 
vitiated air of a crowded and unventilated room. 



26 THE SCHOOL HOUSE. 

The disagreeable odor known as the " schoolhouse smell" is 
occasioned by these substances and the odors given off by the skin, 
stomach, decayed teeth, and unclean persons and clothing. 

Brown Sequard and Arsonval made extended researches into the 
nature of these nitrogenous poisons. They condensed the exhala- 
tions from the lungs of men and dogs and obtained a liquid with 
an alkaline reaction. From two to four cubic centimeters of this 
liquid, injected into the veins of animals, caused a slowing of the 
respiration, dilation of the pupils of the eyes, great muscular 
weakness and a very rapid pulse. When from 10 to 12 cubic 
centimeters were used death speedily followed, even when the fluid 
had been boiled. 

Brown Sequard arranged eight air-tight cages, connected with 
glass tubes from one to the other, and by means of an aspirator air 
was made to pass from cage to cage successively. A rabbit was 
placed in each cage. The one in the first cage received pure air; 
the second, air vitiated by the first animal ; the third, air polluted 
successively by two rabbits, etc. Special provisions were made 
for the removal of excrement. The eighth rabbit died in two days, 
the seventh in three days, and so on till the death of the third one, 
in eight days. The first and second animals remained alive. 

Quantitative analysis of the air in the several cages showed the 
carbonic acid could not have caused the death of the rabbits. With 
bits of pumice stone impregnated with sulphuric acid placed in the 
glass tube between the sixth and seventh cages, the rabbits in the 
seventh and eighth cages remained well. The sulphuric acid 
neutralized the particular poison. 

Claude Bernard made a series of experiments which tend to show 
that the system may gradually, in some degree, acquire a toleration 
of the poisonous principles in rebreathed air. 

A sparrow was inclosed in a glass globe. It hopped about for 
an hour as actively as usual, and then gradually showed signs of 
suffering from rebreathing the air poisoned by its own breath. At 
the end of the second hour another sparrow was placed in the glass 
globe. It was asphyxiated by the foul air" and soon died. At the 
end of the third hour the first sparrow became unconscious. Taken 
out into the open air it soon recovered ; when replaced in the glass 
globe it died at once. 

When expired, air leaving the lungs contains about 400 parts of 
carbonic acid in 10,000 of air, together with other impurities. 

To dilute and remove these products of respiration a large 
quantity of pure air must be supplied. 



THE SCHOOL HOUSE. 27 

Different writers vary as to the amount of air required for the 
good ventilation of occupied rooms. 

Parkes fixes the amount of fresh air per person per hour 

For adult males, 3,500 cubic feet. 

For adult females, 3,000 cubic feet. 

For children, 2,000 cubic feet. 

For a mixed community, 3,000 cubic feet. 

Pettinkoffer recommends 2,100. 

Dr. Billings, from 850 for children 6.25 years old to 2,000 for 
those of i4.88. 

It may be fairly considered that an ordinary adult man expires 
.7 of a cubic foot of carbonic acid per hour, and a person about 
twelve years old averages .6 of a cubic foot, and that 3,000 cubic 
feet of air per hour per person is required for good ventilation. 

Prof. Carpenter, in his excellent work on ventilation, says, " If 
we take the CO., as an index of the character of ventilation, and 
consider that each person uses one-third of a cubic foot of air per 
minute, and that the respired air contains 400 parts in 10,000 of 
CO.,, while the entering air contains but 4, we can calculate the 
amount of air which must be provided to maintain any standard of 
purity desired. The formula for this operation would be as 
follows : 

'* If a = the parts of C0 2 in 10,000 thrown out in respiration, or 
other impurities ; if b = the cubic feet of air used per minute ; if 
n = the standard of purity to be preserved, expressed as the num- 
ber of units of CO._, permissible in 10,000, and C = the number of 
cubic feet of air required, we shall have 

C — a ^ 
~ («— 4) 

" For conditions considered for each adult person, a =400, b = £, 

so the formula becomes 

133 



C = 



(n — 4) 

By taking n as 8, C = 33, and n as 10, C = 22." 

This very nearly agrees with several hundred tests made by the 

writer. 

An approximate rule for calculating the amount of air required 

per capita per hour to keep the CO., down to six parts in 10,000 of 

air in schoolrooms and halls, is by allowing 3,000 cubic feet for this 

purpose. 



28 THE SCHOOL HOUSE. 

For other ratios, divide 6,000 by the difference between normal, 
or four parts in 10,000, and the ratio of purity required. 
Example : 

6 — 4=2, 6,000 -f- 2 =3,000 for 6 parts. 

7—4=3, 6,000-7-3 =2,000 for 7 parts. 

8—4 = 4, 6,000 -r- 4= 1,500 for 8 parts. 

9—4=5, 6,000-7-5 = 1,200 for 9 parts. 

3,000 -7- 60 = 50 per minute for 6 parts. 
2,000 -7- 60 = 33.33 per minute for 7 parts. 
1,500 -7- 60 = 25 per minute for 8 parts. 
1,200 -7- 60 = 20 per minute for 9 parts. 

The standard for schoolrooms adopted by the Massachusetts 
Inspectors of Public Buildings is a minimum of thirty cubic feet of 
fresh air per pupil per minute. 

In many of the well-ventilated school buildings in Massachusetts 
from 40 to 50 cubic feet of fresh air per minute is furnished for 
each pupil. 

Fifty cubic feet of fresh and properly warmed air per minute 
per person is an ample but not excessive amount for good ventila- 
tion in a schoolroom. 

Humidity. 

The amount of C0 2 expelled in respiration is increased greatly 
by external cold and diminished by heat ; increased by moist and 
decreased by dry atmosphere. 

Humidity or moisture in air has much to do with comfort and 
the sensation of heat or cold. 

When the air is saturated with moisture water is deposited on 
bodies which readily conduct heat and are of a lower temperature 
than the surrounding atmosphere. 

No evaporation from the body will take place when the air is 
saturated with moisture. 

When the air is deprived of moisture it evaporates water from 
the body, causing an unpleasant sensation. 

Heat increases the power of air to contain moisture, but to 
remove moisture from the air it must be cooled. 

In schoolhouses where an ample quantity of moderately warmed 
air is supplied there is seldom complaint of dryness of the air. 

It has been found that much better results have been obtained 
when the extra amount of fuel used to evaporate a considerable 
quantity of water has been expended in warming a larger quantity 
of air. 



THE SCHOOL HOUSE. 29 

It is seldom that any special provision is made to moisten the 

atmosphere of schoolrooms- 
Should a little moisture he desired in schoolhouses heated by 

steam, it can be supplied by opening an air-valve in a radiator and 

allowing steam to escape into the air passing over the radiator. 
To feel comfortable and produce the best results in ventilation, 

air should be from 50 to 60 per cent saturated with moisture. 

Lights. 

The lights used in a room are one source of vitiation of air. An 
ordinary gas burner contaminates a quantity of air equivalent to 
that vitiated by from four to five persons, and allowance should be 
made for this quantity in calculating the amount of fresh air 
required. 

In large assembly halls lighted by gas special ventilation should 
be provided above the clusters of gas lights to quickly remove the 
vitiated air and prevent it from mingling with the air of the room. 
Where electric lights are used it is only required to allow for their 
heating effect in large or crowded places of assemblage. 

The size of ordinary schoolrooms should be such that a sufficient 
quantity of fresh air can be introduced and foul air removed 
without causing uncomfortable drafts. 

It is the number of occupants and not the size of the room that 
determines the amount of air that should be supplied. 

Rules calling for the change of air in a room a given number of 
times per hour, without regard to the number of occupants, are 
erroneous, and should not be adopted in designing a system of 
ventilation. 

Testing the Purity of Air. 

It is not always convenient to have a chemical test made in a 
laboratory of the purity of air from a schoolroom or assembly 
hall ; but an approximate test can be made in the schoolroom by 
the use of a simple apparatus known as " Professor Wolpert's Air 
Tester," and, if carefully made, will indicate near enough for all 
practical purposes whether the air is contaminated to such an 
extent as to render it unfit for respiration. 

A comparison of thirteen tests of air for carbonic acid (CO Q ) 
made with a Wolpert air tester and of air taken at the same time 
and placed in glass flasks for laboratory analysis, showed an 
average difference of only sixty-seven one hundredths of one part 
in ten thousand parts of air — the laboratory analyses showing only 



30 THE SCHOOL HOUSE. 

this quantity of carbonic acid (C0 2 ) in excess of the amount 
shown by the Wolpert tester. 

Care must be taken to have a saturated solution of clear lime- 
water and also in using the apparatus. 

The apparatus consists of a simple rubber bulb (A) of a 
capacity of fifty-two cubic centimeters, a glass outlet tube (B) 
with a constriction near its extremity (E). The glass test-tube 
(C), which is twelve centimeters in length and twelve millimeters 
in diameter, has a horizontal mark (F) near the bottom, indicating 
the point to which it must be filled with perfectly clear lime-water 
to contain three cubic centimeters. The bottom of the tube has 
a black mark (D) made by attaching a piece of black glass. A 
small wooden stand, a brush or swab, a vial of vinegar for 
cleaning the tube, and a bottle of perfectly clear and saturated 
lime-water, complete the outfit, and for convenience in carrying 
may all be inclosed in a neat case. 

Where a number of tests are to' be made time may be saved by 
having several test-tubes and bulb outlet tubes in the case, as a 
clean tube should be used for each test. 

DIRECTIONS FOR USING PROFESSOR WOLPERT'S AIR TESTER. 

By S. W. Abbott, M.D., Secretary Massachusetts State Board of Health. 

In order to use the instrument, the lime-water (saturated solution) should 
be poured into the test-tube till it reaches the horizontal mark. Press down 
the bulb with the thumb, so as to expel the air within it as completely as 

possible, and allow it to fill 
Prof. WOLPERT'S AlR TESTER f***S^ with the air oi the apart- 

E; _^ m ^ ■ i .. \ ment, insert the small tube 

into the lime-water nearly to 
the bottom, and again expel 
the air with moderate rap- 
F IG - 10- idity, so that the bubbles may 

rise nearly to the top of the tube, but do not overflow, taking care to continue 
the pressure of the thumb till the small tube is removed from the lime-water. 
Repeat this process until the mark upon the bottom of the test-tube is ob- 
scured by the opacity produced by the reaction of the carbonic acid upon 
the lime-water, the observer looking downwards through the lime-water, 
from the top of the test-tube. 

With very foul air it is necessary to examine the mark after filling and 
discharging the bulb a few times only; with good air it must be filled 
twenty-five times and upwards. 

After each observation the test-tube must be washed out and wiped dry. 
If a white incrustation forms upon the tube, it may be easily removed with 
a little vinegar, after which the tube should be thoroughly washed with pure 
water and dried. 



><te 



^ C7 




THE SCHOOL HOUSE. 



31 



If the mark becomes obscured after filling the bulb ten or fifteen times 
only, the air of an apartment is unfit for continuous respiration. 

The instrument should be used by daylight over a white ground, as a sheet 
of writing paper, and care should be taken not to vitiate the result by trie 
observer's own breath. 

The following approximate table is taken from the article by Professor 
Wolpert, the first column representing the number of fillings of the bulb, 
and the second column the parts per 10,000 of carbonic acid in a given 
sample of air. 

TABLE 1. 



Number 

of 
Fillings. 


Carbonic 

Acid 
per 10,000. 


Number 

of 
Fillings. 


Carbonic 

Acid 
per 10,000. 


Number 

of 
Fillings. 


Carbonic 

Acid 
per 10,000. 


1 


200. 


21 


9.5 


41 


4.9 


2 


100. 


22 


9.1 


42 


4.8 


3 


67. 


23 


8 7 


43 


4.6 


4 


50. 


24 


8.3 


44 


4.5 


5 


40. 


25 


8. 


45 


4.4 


6 


33. 


26 


7.7 


46 


43 


7 


29. 


27 


7.4 


47 


42 


8 


25. 


28 


7.1 


48 


4.1 


9 


22. . 


29 


6.9 


49 


4.1 


10 


20. 


30 


6.6 


50 


4. 


11 


18. 


31 


6.4 


51 


3.9 


12 


16. 


32 


6 3 


52 


3.9 


13 


15. 


33 


6.1 


53 


3 8 


14 


14. 


34 


5.9 


54 


3.7 


15 


13. 


4 35 


5.7 


55 


3.7 


16 


12.5 


36 


5.5 


56 


3.6 


17 


12. 


37 


5.4 


57 


3.5 


18 


11. 


38 


5.3 


58 


3.5 


19 


105 


39 


5 1 


59 


3 4 


20 


10. 


40 


5. 


60 


33 



If the table is not at hand for ready reference, the approximate 
amount of carbonic acid (C0 2 ) in 10,000 parts of any sample of 
air may be obtained by dividing 200 by the number of fillings. 

Example: 200 -M0 = 20 parts of CO 2 
200 -r- 25 = 8 parts of C0 2 



Preparation of Lime-Water for use with 
Professor Wolpert's Air Tester. 

Lime-water purchased at a drug store is ordinarily worthless for 
testing the purity of air, and should never be used for that purpose. 

Inspector John T. White and the writer prepared lime-water for 
use with Professor Wolpert's air tester in the following manner. 

The best unslaked lime made from marble is carefully slaked in 
distilled water in a clean glass bottle, care being taken to put in 



32 



THE SCHOOL HOUSE. 




I'M LIME WATER 



FILTER 



but a small quantity at a time to prevent breaking the bottle by the 
heat generated during the slaking. 

After the lime has settled the first water is decanted off and the 
slaked lime carefully washed with distilled water, allowing the lime 
to settle before pouring off the wash water. The bottle is then 
nearly filled with distilled water and shaken at intervals for several 

days, the bottle being carefully closed 
during the time with a tight-fitting paraf- 
fined cork or ground-glass stopper. 

A considerable quantity, say one-half 
inch or more, of the undissolved lime, 
should always remain in the bottom of the 
bottle. 

After the lime has thoroughly settled 
and the water has become perfectly clear, 
a sufficient quantity may be transferred to 
a small bottle for use with the apparatus. 
The following described apparatus is 
used to prevent the linie-water absorbing 
carbonic acid from the air while being 
poured from one bottle to the other. 

The large bottle (A) containing the 
clear lime-water (L), with the undissolved 
lime (M), in the bottom is fitted with a 
stopper (C), through which a glass tube 
(D) is passed and extended well below 
the surface of the lime-water, but not too 
close to the undissolved lime ; and the glass 
tube (D) is connected with another glass 
tube (I) by the rubber tubing (E) which 
has inserted into it a larger glass tube or long bulb (F) consist- 
ing of two parts held together by a piece of rubber tubing (G). 
The larger tube or bulb is made in two pieces to allow cotton fiber 
as a filter (H) to be easily inserted or removed. The lower glass 
tube (I) passes into the small bottle (B), the mouth of which is 
loosely filled with cotton (K) . 

The larger bottle (A) being placed on a table or shelf, and the 
small bottle (B) on the floor or a lower shelf, the lower end of 
the tube (I) is placed in the mouth of the operator and the air is 
sucked out till the lime-water flows freely, the siphoning being 
continued till sufficient lime-water has passed through to clear the 




Fig. 11. 



THE SCHOOL HOUSE. 33 

tubes. The lower tube (I) is inserted into the lower bottle and 
cotton fibre loosely placed in its mouth. 

The clear lime-water will then be siphoned into the small bottle 
without coming in contact with the outer air. 

When filled, the small bottle must be carefully closed with a 
tight-fitting ground glass stopper. 

Measurement of Air. 

An anemometer is an instrument for measuring the velocity of 
air currents. It consists of a number of blades set at an angle on 
a shaft and inclosed within a rim or circular casing. The blades 
are constructed of light-weight metal, and the shaft is provided 
with bearings to reduce the friction as much as possible. The 
movement of the air in the direction of the axis of the shaft causes 
the shaft to rotate, setting in motion a train of gears, by means of 
which the index hands indicate the number of revolutions and the 
velocity. 

The number of index hands required depends upon the use for 
which the instrument is intended. 

Many of those in common use have but two index hands, one 
index for ioo revolutions, and one for iooo. 

Anemometers intended to be kept running in one place for a 
considerable time have more index hands, each index successively 
recording ten times the next lower index. 

The four-inch " Byram's " with two indices has been found by 
the writer to be a very convenient sized and reliable instrument. 
Those of larger size are too cumbersome, and cannot be used to 
advantage in testing the velocity in different parts of a small duct 
or opening. The small two-and-one-half inch size, while con- 
venient to carry in the pocket, is not usually quite as reliable as 
the four-inch pattern. 

A correction table is usually furnished by the manufacturer for 
each instrument, which gives the correction to be allowed for 
different speeds. 

For convenience it is well to have a special adjustment made, 
according to the work to be done, by some reliable party having 
the proper means for rating the instrument. 

A normal rating at 300 feet per minute is a convenient speed for 
ordinary schoolhouse work. 

Where the instrument is used frequently it is advisable to have it 
tested at intervals. 



34 



THE SCHOOL HOUSE. 



If a number of instruments are used by several persons who can 
meet occasionally at a given place, it is advisable that one carefully 
tested instrument be kept as a standard by which others can be 
tested without the expense and delay of sending them away. 

A convenient way of testing by means of the standard instrument 
is to cover with a board an opening through which a constant 
current passes, preferably one through which the flow is caused by 
a fan. In the board cut two openings side by side, into which the 
two anemometers can be easily placed, but fitting reasonably tight. 
By changing the anemometers from one opening to the other and 
noting the velocity for a given time, fairly good comparisons can be 
had as to the running of the instruments. - 

The speed of the fan wheel can be adjusted by changing the 
angle of inclination of the blades. When the fan wheel is running 
too slow a greater speed will be recorded by reducing the angle or 
flattening the blades. If running too fast the angle should be 
increased. 

In changing the angle of the blades care should be taken to have 
the pitch of each blade the same. 




Fig. 12. 



After the instrument has been tested and rated, and before using 
it, a template can be made of stout sheet metal or wood which will 
fit the pitch of the blades. 

The accompanying diagram shows the form of the template. 

By placing the edge A-A on the top of the casing, with the 
perpendicular edge B resting on the inner side of the casing, the 
inclined side C will give the pitch or inclination of the blades. 

An accurate instrument is required to obtain correct measure- 
ments of the velocity. 



THE SCHOOL HOUSE. 



35 



In measuring the velocity of air at inlets and outlets, especially 
in school-rooms, care must be exercised to obtain a correct average 
velocity ; also the net available or working area of the opening. 

At an inlet or outlet from a room the velocity of the air currents 
varies materially in different parts of the opening. This variation 
is owing to a variety of causes, of which the form and direction of 
the duct or shaft is one of the principal. The ordinary inlet for 





„&^ 

m^:- 
<*?,* 



V/i 



Fig. 13. 



Fig. H 



supplying air to a schoolroom should have a curve at the top, and 
the bottom of the inlet should have the wall on the front of the duct 
cut away, curved, or beveled down. The tendency of the air flow- 
ing up the warm-air flue is to strike against the top of the flue and 
be deflected into the room. Where the top is properly curved, the 
direction of the warm air current is changed in a more satisfactory 
manner than when the top is flat. If the bottom of the opening is 
flat and horizontal, the current is carried up too high before it 
changes its direction. This is particularly noticeable in flues 
having walls eight inches thick with the added thickness of 
studding and plastering. 

The available or working area of the opening is often greatly 
reduced from this cause, and in some cases one-third or more of 
the area is not available and the volume of air which should pass 
through the whole opening is forced into a space one-third or more 
smaller than it should be, thereby increasing the velocity to an 
undesirable point. 

Upon holding an anemometer on the lowest part of the inlet 
opening, the fan wheel will sometimes indicate an inward or 
reversed current, caused by an eddy above the flat top of the front 
wall of the duct. 



36 



THE SCHOOL HOUSE. 



In other cases the current will be stronger at one end of the inlet 
opening than at the other. 

Again it will be diagonally up and across the opening, or it may 
be in the form of an arch, or strong at one end and weak at another 
point in a perpendicular line. 

Occasionally the lowest velocity will be in the center of the 
opening. These different currents are produced by offsets or 
changes in the form and direction of the duct before it reaches the 
opening. 

In measuring the inflowing air the various currents and velocities 
must be carefully noted in order to obtain a correct average. 

In the greater number of cases the velocity will be highest at the 
top of the inlet opening, decreasing down to a point towards the 






Fig. 15. 



Fig. 16. 



Fig. 17. 



bottom, where no movement of the anemometer wheel will take 
place. 

In measuring the amount of air coming through the inlet it is 
advisable to place the anemometer in front of the bottom of the 
inlet and gradually raise it till the top of the blades will strike the 
incoming current, then note this point and cover the opening below 
it with a piece of rubber cloth having small hooks on the upper 
edge to fasten to the register or grill over the opening. This will 
cause any incoming air below this point to be sent through the 
upper and uncovered part of the opening. 

Then measure the length and height of the uncovered part of the 
opening for the effective or working area. 

If a register face of any of the common cast-iron patterns is used 
to cover the opening a deduction of one-third should be made from 
the working area as found by the above measurement. With some 
cast-iron register faces a larger deduction will be required. 

With the ordinary wire grill pattern over the opening about 
one-tenth will be a fair deduction. With some patterns it may be 
one-eighth. 




THE SCHOOL HOUSE. 37 

Care should be taken to hold the anemometer with the edge of 
the casing parallel with the register face or grill. Air striking the 
blades at different angles will give different readings on the index. 

It is usual to take three, five or nine measurements with the 
anemometer placed as shown in diagrams, Figures 15, 16 and 17. 

If the opening is circular the anemometer may be placed as 
shown in Fig. 1<S. 

If a very careful measurement of the air is required it may be 
advisable to construct a frame the size of the opening to be 
measured and one foot deep, and divide the area 
into squares with sides of six inches by stretching 
pieces of cord across the outer edge of the frame, 
then holding the anemometer for a given time — say 
one minute each — with the center of the wheel 
opposite the intersections of the cords. 

The total of the different readings of the index 
divided by their number will give a fair average of the velocity of 
the current. 

The average velocity, multiplied by the net available square feet 
of opening, will give the number of cubic feet of air passing in a 
given time. If the time of each reading of the index is one minute 
the amount will be in cubic feet per minute. This, divided by the 
number of seats in the room, will give the number of cubic feet of 
air supplied per minute for each seat. 

If the amount per hour is* required, multiply the supply per 
minute by sixty. 

The practice of moving the anemometer over different parts of 
the opening while taking a measurement is not a good one, espe- 
cially if the lower part of the opening is not an available or 
working area. 

If the instrument is held at the top of the opening till the fan 
wheel has acquired the greatest velocity obtainable in that position, 
and is then quickly moved to the bottom of the opening, the 
readings will be incorrect. The momentum of the wheel will 
continue it in motion till after it is gone below the available work- 
ing area, and if the instrument is raised again to the top of the 
opening the speed will be again raised to the high point. 

The writer recalls an instance in which a person who claimed to 
be an expert heating and ventilating engineer had installed a 
heating and ventilating apparatus in a new schoolhouse. 

He had succeeded in securing from the building committee a 
contract for the work without giving any guarantee that the work 



38 THE SCHOOL HOUSE. 

should be up to the state requirements, or that it should be tested 
by the state inspector. 

Being desirous of obtaining his pay, and being a good talker, he 
had induced the building committee to be present at the building 
on a day when the conditions of temperature and wind were 
favorable for obtaining good results. 

His talk to the committee was like this : " Now, gentlemen, I 
have given you a first-class piece of work, and in order that you 
may see what excellent results we have obtained I have asked you 
to be present today and see the apparatus tested. 

" To satisfy you that the test is fairly made I will ask one of you 
gentlemen, to give me the time by your watch, one minute, while 
I use this anemometer to ascertain at what velocity the air enters 
the room." Showing the anemometer to the committee, he 
explained its use and how to read the indices, and had them note 
the position of the hands of each index. 

Holding the instrument near the top of the opening, he started 
and stopped it at a signal from the man holding the watch. 
Observing the index, the committee noted the velocity recorded to 
be 550 feet per minute. Then measuring the full area of the 
opening, which was covered by an ordinary 'register face, he used 
his pencil and paper, showing the committee the figures, of which 
they took a copy. "Now, gentlemen, the opening is 30 by 20 
inches, which made an area of 600 square inches, or 4.16 square 
feet. The velocity is 550 feet per minute, which gives you 2,288 
cubic feet of fresh air per minute for the 48 pupils, or 47-f cubic 
feet per minute for each scholar. You will see this is very much 
better than I told you I would do." 

The committee were satisfied, and paid the bill. After a time 
complaints were made of defects in the system, and the state 
inspector was asked what could be done to remedy them, as the 
contractor would not do it. 

When a test was made by the inspector the committee were 
greatly surprised to see the report of the air actually supplied. 
Other defects were pointed out in the apparatus, and several 
hundred dollars were expended before the apparatus was made to 
do fair work. 

The volume of air and its weight per cubic foot change with the 
temperature. 

In measuring and computing the volume of air its temperature 
at the time of measurement should be taken into account. 



THE SCHOOL HOUSE. 39 

In comparing one measurement with another the volumes should 
all be reduced to corresponding volumes at zero. (Absolute 
T = 46o° below zero.) 

Reduce both the original and final temperature to absolute 
temperatures. Multiply the original volume by the final absolute 
temperature and divide by the original absolute temperature. The 
quotient will be the final volume. 

If V=the original volume, V x = final volume, Tj = original 
absolute temperature, and T = final absolute temperature; then 

v _ VT = 
1 TT 

Example : What will be the volume of 1800 cubic feet of air at 
a temperature of 100 degrees F. when it is cooled to 70 degrees F. ? 

1800 ( 460 + 7 °) = 1703.57 cubic feet. 
460 + 100 

Wind — Velocity and Pressure. 

The pressure of the wind varies as the square of the velocity, 
or P~V 2 . 

The square of the velocity in miles per hour multiplied by 
.005 = P. 

The square root of 200 times the pressure equals the velocity, or 
"^200 X P = V. 

To find the rate at which air is moving, divide the velocity in 
feet per minute by .88 ; the answer will be in miles per hour. 

Example : 300 feet per minute = 300 -f- .88 = 3.409 miles per 
hour. 

To find the pressure in pounds per square foot, multiply the 
square of the velocity in feet per second by .0023 ; the result will 
be pounds pressure. 

Example : 300 feet per minute = 5 feet per second, and 
5 X 5 X .0023 = .0575 pounds. 

The shape of the surface obstructing the wind greatly modifies 
the pressure. 

The pressure upon a globe, or a hemisphere with the convex 
side towards the wind, is only about one-half the pressure on a flat 
surface of equal diameter. 



40 



THE SCHOOL HOUSE. 



TABLE 2 

Showing the Number of Miles per Hour and Pressure in Pounds per 

Sojjare Foot on Flat Surfaces at Right Angles to the 

Current, at Velocities per Minute. 







Pressure 








Pressure 




Feet 


Miles 


in Pounds 




Feet 


Miles 


in Pounds 




per 


per 


per 

Sq. Foot. 


Character of Wind. 


per 


per 


per 
Sq. Foot. 


Character of Wind. 


Minute. 


Hour. 




Minute. 


Hour. 




10 


.113 


.0000 




550 


6.249 


.1930 




20 


.227 


.0002 




600 


6.818 


.2300 




25 


.284 


.0004 




650 


7.386 


.2968 




30 


.340 


.0006 




'700 


7.954 


.3125 




35 


.397 


.0008 




750 


8.522 


.3593 




40 


.454 


.0010 




800 


9.090 


.4087 




45 


.511 


.0013 




850 


9.658 


.4616 




50 


.568 


.0016 




900 


10.227 


.5175 


Gentle breeze 


55 


.625 


.0019 




950 


10.795 


.5763 


Gentle breeze 


60 


.681 


.0023 




1000 


11.363 


.6384 


Fresh breeze 


65 


.738 


.0027 




1500 


17.405 


1.4375 


Light wind 


70 


.795 


.0031 




2000 


22.727 


2.5553 


Brisk wind 


75 


.852 


.0036 




2500 


28.407 


3.9918 


Strong wind 


80 


.909 


.0041 


• 


3000 


34.090 


5.7500 


Strong wind 


85 


.966 


.0046 




3500 


39.772 


7.8255 


High wind 


90 


1.022 


.0051 


Hardly perceptible 


4000 


45.454 


10.2202 


Gale 


95 


1.079 


.0057 




4500 


51.131 


12.9375 


Gale 


100 


1.136 


.0063 




5000 


56.818 


15.9709 


Gale 


125 


1 420 


.0100 




5500 


62.499 


19.2982 


Strong gale 


150 


1.704 


.0143 




6000 


68.181 


22.9954 


Violent gale 


175 


1.988 


.0195 


Perceptible breeze 


6500 


73.861 


26.9764 


Violent gale 


200 


2.272 


.0255 


Pleasant breeze 


7000 


79.545 


31.3020 


Hurricane 


250 


2.840 


.0398 




7500 


85.225 


35.9375 


Hurricane 


300 


3.409 


.0575 




8000 


90.909 


40.8868 


Hurricane 


350 


3.977 


.0781 




8500 


96.589 


46.1554 


Hurricane 


400 


4 545 


.1021 




9000 


102.272 


51.7500 


Tornado 


450 


5.113 


.1294 




9500 


107.952 


57.7447 


Tornado 


500 


5 681 


.1596 




10000 


113.636 


63.8837 


Tornado 



CHAPTER III. 



SOME IDEAS OF VENTILATION. 

THE law requiring the ventilation of public and school 
buildings in Massachusetts was passed in 1888. 
The standard was fixed by the inspection department 
at a minimum of thirty cubic feet of fresh air per minute per person : 

Not because that was all that is required for good ventilation ; 
but because it would greatly improve existing conditions and would 
be about as much as could then be reasonably obtained without 
incurring considerable additional expense in a large number of 
school buildings. 

Many persons claimed this amount was excessive and could not 
be supplied to the pupils in a schoolroom without creating almost 
a gale in the room. 

Some of the heating and ventilating contractors refused to guar- 
antee any such amount, claiming that such a quantity of air could 
not be properly heated. 

At the present time there is no difficulty in furnishing that amount, 
and perhaps the larger part of the work designed for modern school- 
houses in Massachusetts now gives from forty to fifty cubic feet of 
fresh air per minute for each person accommodated in a school- 
room. A guarantee is required by the Massachusetts inspectors 
that certain results will be obtained before their approval of plans 
and specifications for heating and ventilating is given. 

THE REQUIREMENTS OF "FORM NO. 83," INSPECTION DE- 
PARTMENT MASSACHUSETTS DISTRICT POLICE, ARE AS 
FOLLOWS : 

In the ventilation of school buildings the many hundred examinations 
made by the inspectors of this department have shown that the following 
requirements can be easily complied with : 

1. That the apparatus will with proper management, heat all the rooms, 
including the corridors, to 70° F. in any weather. 

2. That, with the rooms at 70° and a difference of not less than 40° 
between the temperature of the outside air and that of the air entering the 
room at the warm-air inlet, the apparatus will supply at least thirty cubic feet 
of air per minute for each scholar accommodated in the rooms. 

3. That such supply of air will so circulate in the rooms that no uncom- 
fortable draught will be felt, and that the difference in temperature between 



42 THE SCHOOL HOUSE. 

any two points on the breathing plane in the occupied portion of a room will 
not exceed 3°. 

4. That vitiated air in amount equal to the supply from the inlets will be 
removed through the ventiducts. 

5. That the sanitary appliances will be so ventilated that no odors there- 
from will be perceived in any portion of the building. 

To secure the approval of this department of plans showing methods or 
systems of heating and ventilation, the above requirements must be guaran- 
teed in the specifications accompanying the plans. 

With a mechanical system of ventilation the allowance of 40 
degrees in temperature (Section 2) should be omitted in the 
specifications, as it was intended to apply to gravity systems. 

Many persons, some of them members of school committees, 
while they readily admit in a general way that pure air is essential 
to health, do not seem to be aware of the danger of impure air as it 
exists in an ordinary schoolroom. They seem to think that as some 
schoolhouses never have been ventilated there is no occasion for any 
anxiety about them now. 

Many old school teachers say they never had any difficulty in ven- 
tilating their schoolrooms by means of the windows. Windows are 
made to admit light and not air, and except when the temperature 
of the outer and inner air is so nearly equal that the air can be per- 
mitted to circulate freely through the rooms they should never be 
depended upon for ventilation. 

Besides, it costs no more to admit the same amount of air in the 
proper way, and warm it before it enters the room, than to let it in 
cold at a window and heat it after it is in. 

The saving which some people think is made by admitting cold 
air through the windows, or by means of patented devices, is 
effected only so far as the amount of fresh air is restricted. 

The writer remembers a hearing given by the legislative com- 
mittee having the proposed ventilation law under consideration. 

A man of good standing in his town, who had held various official 
positions, among them that of school committeeman, appeared in 
opposition to the bill before the legislative committee at one of the 
hearings. He said, "Gentlemen, this talk about carbonic acid is 
all humbug. We know that carbonic acid is heavier than air. You 
may remember what we were taught at school about putting pieces 
of candle on an inclined board and pouring carbonic acid out of 
a jar — that it would flow down the board and put out the flame of 
the candles. You know that a candle will not burn in a deep hole 
or well where carbonic acid has settled to the bottom. Now all you 



THE SCHOOL HOUSE. 43 

have got to do to get rid of this carbonic acid in a schoolroom is to 
cut a hole in the floor and let it run down into the cellar, and if you 
don't want it in the cellar just cut some holes in the outside walls at 
the floor and let it run outdoors." 

It was quite evident that this man was not familiar with the 
law of diffusion of gases, or with the condition of the warm exhala- 
tions from the lungs. 

Another man, talking with a friend, stated, " This matter of ven- 
tilation is all humbug. When I went to school there was no ventila- 
tion in the schoolhouse. Anyone can see I am strong and hearty, 
although I am well along in years." He was asked, " How many 
were there in your school when you went ? " He replied, " About 
forty." How many of them are living now ? " was the next ques- 
tion. After considerable thought he replied, " Only two, as far as 
I know." The friend said, " Well, the balance appears to be on 
the wrong side of the account, if your theory is correct." 

In a small country school the inspector had induced the school 
committee to install a jacketed stove, build a vent shaft and put in 
a small heater to cause an outflow of foul air through the vent shaft. 
This gave fair ventilation for the number of scholars attending. 
Some three years later the inspector again visited this school- 
house. The jacketed stove had been removed and an old-fashioned 
wood-burning stove had been substituted. The foul air outlet at 
the floor level had been carefully boarded up. On opening the 
iron feed door and looking into the vent shaft it was found that 
birds had used the top of the heater as a place on which to build 
nests. There were two nests, one upon the other, indicating that 
the heater had not been used for two years. When the school 
committee were called upon to explain their reason for making the 
change the reply was, " It was no use to put any ventilation in that 
building. When the air got bad the doors and windows could be 
opened. It cost more for fuel than when the wood-burning stove 
was in use." 

I am glad to say that committee do not now have charge of the 
schools, and the town now has three modern and well-ventilated 
schoolhouses. 

In another town a jacketed stove had been installed in a one- 
room schoolhouse. After a year had passed complaint w r as made 
that the system of ventilation was a complete failure, and that the 
schoolroom could not be heated and the air w T as bad. When the 
inspector visited the building he found that a board had been care- 



44 THE SCHOOL HOUSE. 

fully fitted over the fresh-air inlet to the jacketed stove and a round 
hole two inches in diameter had been cut in the board. The cause 
of the failure to heat and ventilate this room was apparent. 

In one city in which modern heating and ventilating had been 
provided in several schoolhouses, the inspector found that no heat 
was used in the vent shafts in any of the buildings. When the 
janitors were asked why they did not use the vent shaft heaters in 
mild weather, they gave as a reason that the superintendent of 
schools had given them positive orders not to use the vent shaft 
heaters, as he considered it a useless and extravagant waste of fuel. 

Education is, however, reducing the number of those who oppose 
providing good ventilation in schools, churches and places of 
assemblage. The necessity of a large amount of fresh air and the 
practicability of obtaining it are fast coming to be universally 
admitted. 

Nor is the fear at first entertained of an enormously increased 
expense likely to be realized. 

Good ventilation undoubtedly costs money, but the expense of 
the new methods as compared with the old is more with the first 
cost of the appliances than with the cost of supplying and remov- 
ing the air after such appliances have been put in. 

Circulation of Air. 

In designing a system of heating and ventilation one of the most 
important points to consider is the proper circulation of the air 
used for conveying the heat and also for removing the impurities 
thrown off by the occupants of the rooms, or from any other source 
of contamination. 

For many years it would seem that very little attention was given 
to this matter. The only thought apparently was where the inlets' 
and outlets could be most conveniently placed, without regard to 
their efficiency. 

On the proper location of the inlets and outlets will depend 
the efficiency and economy of the heating and ventilation. A large 
amount of heat and air may be brought into a room, but if it is 
allowed to escape without proper circulation very little benefit will 
be derived. 

We have seen schoolrooms where the warm air was brought in 
through a register in the floor and was allowed to escape through 
a register in the ceiling or side wall near the ceiling and almost 
over the inlet. 



THE SCHOOL HOUSE. 45 

In other cases the inlets and outlets were placed in the outer and 
most exposed corners of the room, where the fresh air that leaked 
in around the windows was taken out through the vent ducts, 
having done nothing but cooled the air in the immediate vicinity of 
the vent duct. 

Again, the warm fresh air has been brought in through an inlet 
properly located, but the outlet being placed directly opposite the 
inlet, the air would pass across the room and go out at the outlet, 
doing but very little good; in fact, only causing uncomfortable 
drafts on whoever had the misfortune to be located between the 
inlet and the outlet. 

In many instances the warm air would be taken in at the inner 
or warm angle of the room while the outlet was placed near an 
outside or exposed wall. 

Sometimes it would appear that the designer of the system had 
devised some scheme that would do the work in the most unsatis- 
factory manner. 

In one " system " that was installed in many school buildings 
(but which is not at this time allowed in Massachusetts), the outlets 
were long narrow openings placed at the floor level in the outside 
walls and often under the windows. The air was taken across 
under the floors between the floor timbers and down into what was 
called a "foul air gathering room," and then passed over screens 
placed below the seats in the sanitary closets (perhaps the term 
unsanitary closets would be more appropriate). Here it was 
supposed to dry the excrement, which was afterwards to be burned 
by pouring a quantity of oil over it and then setting the oil and 
accumulated paper on fire. 

In such a " system" the air which came into the room around 
the windows, or was cooled on the glass surface, would drop down 
to the floor, and, if there was a strong fire in the large heater in the 
ventilating shaft, after having been passed through the space under 
the "cremating closets" would be taken out of the building, while 
the vitiated air, especially in the inner or warm parts of the room 
occupied by the pupils, would remain. 

By chemical tests the writer has many times found the air to be 
purer in the so-called "foul air gathering room " than about the 
seats where the pupils were located. 

Another serious defect in this " system" was the danger of odors 
and gases being forced back into the schoolroom when there was 
no fire in the vent shaft heater, or where the vent shafts came 
through the roof in a location to be affected by adverse air currents 
or wind. 



46 THE SCHOOL HOUSE. 

In addition to these defects was the danger from fire. The rough 
floor timbers and boards soon became covered with fine particles 
of lint and other material which was drawn in by the air current. 
If fire from any cause should get into these under-floor ducts it 
would spread with great rapidity through the entire building. 

The Massachusetts law which prohibits wooden ducts for heating 
and ventilating public buildings soon put a stop to the further 
extension of this dangerous " system." 

Another " system " was introduced into some school buildings, 
by means of which it was proposed to draw the air down from the 
upper stories through a duct which entered the bottom of the vent 
shaft, and which was enlarged at each story as it came down to 
the basement, where air was to enter the vent shaft and, after 
being warmed by a "stack heater," or small furnace, was to 
escape through the central vent shaft. 

The opening from the upper story room was supposed to be 
sufficient to furnish the required ventilation for the room in which 
it was placed. The duct was enlarged at the next floor below to 
twice its original size, and so on. 

The designer of this "system" did not take into consideration 
the fact that moving air will follow the line of least resistance. 
It was often found that, while an anemometer would show a 
velocity of 500 feet or more per minute at the lower opening, the 
movement of air at the upper opening was not strong enough to 
cause any movement of the anemometer wheel. 

Several other "systems" were brought forward and introduced 
by various experimenters, who in many cases tested their theories 
at the expense of various cities and towns. 

In 1888 and 1889 the writer, in company with State Inspector 
the late John T. White, made a large number of tests of the 
circulation of air in different schoolhouses in Massachusetts, by 
means of smoke, and otherwise, to ascertain what should be the 
proper location of the inlets and outlets to secure a good circula- 
tion of the air and heat ; also, to determine the proper size and 
form of inlets and outlets for the ventilation of schoolrooms. 

It was found from these tests that the best results would be 
obtained by varying the location of the inlets and outlets to meet 
the different locations of the cold or exposed walls. 

In a schoolroom having two cold and exposed walls the inlet 
should be placed with the lower part about eight feet above the 
floor (allowing the room to be twelve feet high) and in one of the 
warm sides, about four or five feet from a cold or exposed wall. 



THE SCHOOL HOUSE. 



47 



The top of the inlet should be curved so as to throw the air 
forward and across the room to the most exposed or cold angle of 
the two outer walls, the outlet being placed at the floor level and 
near the inner or warm angle of the room. 

The air, on entering the room though the inlet opening (which 
should be covered by a grill of about one-eighth-inch wire of 
diamond mesh pattern, the mesh being about one and one-half to two 
inches long at its greatest dimension, and set in a channel iron 
frame) passes first forward and upward and spreads across the ceil- 
ing to the outer wall of the room, being at the same time drawn 
toward and down the windows by the cooling effect of the glass 
surface, continuing around the room with a falling spiral movement, 
diffusing throughout the room 
and gradually falling and drawing 
toward the outlet. 

In a room considerably longer 
than wide and with three exposed 
or cold walls, the inlets should be 
placed at the same height above 
the floor as in the preceding case, 
but in this case there should be 
two inlets and one outlet. The 
inlets should be in the inner or 
warm wall, about the same dis- 
tance from the cold end walls as 
in the first instance. The outlet 
should be placed at the floor level, but as near as practicable in 
the center of the inner or warm wall. 

The entering air will spread across the ceiling to the cold walls, 
as in the case of the room with two cold and two warm walls, but 
a considerable part of the two currents will meet near the center of 
the longest outside wall and the whole will be drawn down and 
back to the outlet near the center of the warm wall. 

In a room having three cold and one warm wall, but with the 
warm wall on one end of the room, the inlet should be placed about 
eight feet above the floor near the centre of the warm wall, and the 
outlet placed at the floor level, nearly under the inlet. The enter- 
ing air will spread across the ceiling to the three outside cold walls, 
where it will fall and be drawn back from all sides across the room 
to the outlet. 

In a room having one cold and three warm walls, the inlet and 
outlet can be placed either as in the first or last mentioned instance. 




Fig. 19. 



48 



THE SCHOOL HOUSE. 




Fig. 20. 



(Figures 19 or 21 .) Good results will be obtained either way, and 
the location can be determined by considering which method will 
be best adapted to the construction of the building and the general 
location of other heat and vent ducts. 

A volume of air heated from the freezing to the boiling point of 

water, barometer 30 
inches, expands ap- 
proximately 1/500 
(1/490) for each de- 
gree F. it is raised. 

If the air of a 
schoolroom is 40 de- 
grees higher than that 
of the exterior air its 
volume has been in- 
creased approximately 
2/25 ; consequently it 
is lighter than the exterior air and, tends to rise. 

A cubic foot of air at 60 degrees F., dew point 40 degrees, 
barometer 30 inches, will weigh 534.27 grains. 

A cubic foot of expired air at 95 degrees F., dew point 85 degrees, 
containing 12.78 grains of vapor, and, say, 4 per cent of carbonic 
acid, will weigh only 494.12 grains, or 7.5 
per cent less. This tendency to rise is fur- 
ther increased by the heat given off by the 
body, which warms the air in immediate 
contact with it. 

At first sight it would seem easier to ven- 
tilate a schoolroom by the general upward 
movement of the air, because of its tendency 
to rise when first exhaled from the lungs. 

If the air is admitted at the floor and taken 
out at the ceiling there is established a 
current between the inlet and the outlet, 
leaving the foul air in some parts of the 
Fig. 21. room almost unmoved, and only slowly and 

partly drawn into the current. 

Another objection to this method of ventilation is the difficulty 
of properly heating a schoolroom by it. The great loss of heat 
necessitated thereby calls for the consumption of a much greater 
quantity of fuel. The hot air is drawn off rapidly from the top, 
while the cold air remains at the bottom of the room. 




THE SCHOOL HOUSE. 49 

From whatever point the warm fresh air is admitted to the 
schoolroom, it rises at once to the ceiling, and the sooner it reaches 
that point without being contaminated the better it will be. 

By the law of diffusion of gases the expired air would in time 
undoubtedly be diffused throughout the whole room, as would also 
the poisonous nitrogenous matter exhaled from the lungs and bodies. 

By exhausting the foul air from the bottom a downward move- 
ment of the warm air entering at the top of the room is maintained, 
and as the poisonous products of respiration must be diluted and 
removed by the introduction of pure air, a circulation within the 
room is maintained which will produce the required results. 

If we make a careful inspection of the course of hot air 
admitted through a register in the floor we will see that the current 
of hot air goes directly to the ceiling, and that a portion of the 
surrounding cooler air is carried up with it by friction, and that 
this air was drawn from near the floor. The air thus carried up 
was foul air, and should have been carried off through the vent duct. 

The question of admitting the fresh air at the top of the room 
is not determined by the natural movement of carbonic acid or any 
other impurity, or by the gravity or weight of the air as it comes 
from the lungs. 

In cold weather the fresh air must be warmed to a number of 
degrees above the temperature at which we wish to have the room 
at the breathing line. Heated air will go to the top of the room, 
no matter where we admit it, and its distribution will begin there. 
By leading it there in pipes or flues we avoid carrying up dust and 
foul air. with it, and we can locate the inlets and direct the flow of 
air so as to distribute it more evenly than if we admit it at the 
floor. The air will spread over the ceiling and be drawn to the 
outer walls by the falling current caused by cooling on the 
windows and walls. It then descends to the floor, and may be best 
taken out at the bottom of the room. 

Wherever there is any attempt at a proper system of ventilation 
in a schoolhouse, the walls and ceiling should be made as impervi- 
ous as practicable both to air and heat. 

The ceiling of an ordinary schoolroom contains about nine 
hundred square feet of surface, and generally consists only of laths 
and a coat of mortar. In the attic there is frequently only a single 
floor over the ceiling of the room below, and frequently no floor 
at all. 

With the temperature of the air at the top of the room from 
80 to 90° F., and that of the attic at thirty degrees, or lower, as it 



50 THE SCHOOL HOUSE. 

may be on a cold day, it is easy to see what an amount of warm 
fresh air is lost. This is particularly noticeable in the plenum 
method. 

The objection has been made to the exhaust system of ventilation 
that the air is drawn into the room from every crevice in the walls, 
floor and ceiling, and also from the corridors and clothes rooms. 

The objection can also be made to the plenum system that the 
impure air is driven out at every crevice and opening, thus possi- 
bly forming accumulations of foul matter and disease germs in 
places that cannot be reached to be cleaned ; also that a consider- 
able part of the warm fresh air which enters at the inlet at a 
higher temperature than at the breathing line escapes through the 
ceiling and walls before it has circulated and reached the breathing 
plane, thereby causing a loss of heat that could be utilized within 
the room. 

With the plenum system there is always a leakage of air from 
the room, as there also is with a gravity system when the exhaust 
is insufficient, and if this leakage takes place from air at 90 to 100 
degrees it is evident that more heat will be lost than from air at 
70 degrees. 

There is little difficulty in forcing 4000 cubic feet of air per 
minute with a plenum fan into an ordinary schoolroom when the 
outlet is closed and windows and doors made as tight as 
practicable, and hardly a perceptible rise in the barometer can be 
noted. This will show the effect of leakage. 

In some cases, especially where fans or blowers are used, as in 
the plenum system, to force air into a schoolroom, and where the 
exhaust is very deficient, there is a tendency to force the air out of 
the room as it falls on the cool walls and also through the ceiling. 
As the warm air goes directly to the top of the room and at least 
three-quarters of the leakage is above the breathing plane, a large 
quantity of the fresh air will not reach the pupils. 

As the result of many observations the writer is led to believe 
that a schoolroom supplied with 1,500 cubic feet of air per 
minute, with properly located fresh warm-air inlets and foul -air 
vent flues, will have the air at the breathing plane kept as pure as 
it will when supplied with 2,500 cubic feet per minute with no 
proper provisions for circulating and removing the air. 

The economy of heating and forcing this extra 1,000 cubic feet 
of air into a room has not yet been satisfactorily explained. 

Many persons who admit the necessity of supplying a large 
quantity of air for ventilation fail to appreciate the importance of 



THE SCHOOL HOUSE. 51 

the work done by the ventilating duct or [chimney. While they 
acknowledge the good work done by an open fireplace in removing 
foul air from a room, they apparently do not appreciate the fact 
that the fireplace takes the air from the bottom of the room. The 
ventilating duct opening from the bottom of the room works in the 
same way, and when properly located will do the work with far 
less expenditure of fuel than the open fireplace. 

It has been the experience of the writer that when a well-adjusted 
combination of the plenum and exhaust systems is installed in a 
school building, more economical and satisfactory results are 
obtained than by the use of either system independently. 

When the exhaust is a little in excess of the plenum, say about 
five per cent, the heat that is lost by leakage by the plenum method 
is utilized to warm the air drawn into the room through the outer 
walls, but in so many small places that uncomfortable drafts are 
not produced. 

When the corridors, clothing and sanitary rooms are properly 
ventilated there is little clanger of foul air reaching the class-rooms 
from such sources. This is at variance with the recommendations 
of many persons, but it is the experience of the writer in making 
many hundred tests of the heating and ventilation of schoolrooms. 

The subject of leakage of air and heat has not apparently received 
the attention from heating and ventilating engineers which it 
requires. In certain cheaply constructed buildings, where a very 
strong exhaust was in use, the writer has frequently found twice and 
sometimes three times as much air going out at the outlet as was com- 
ing in at the inlet. This is excessive, and should be guarded against 
by proper adjustment of dampers and heat in the exhaust flues. 

In some of the mechanical systems of heating and ventilation in 
use in school buildings the velocity of the air at the inlets is too 
great and the size of the pipes or ducts is too small. Six feet 
velocity per second at the inlet is enough, and five feet per second, 
or three hundred feet per minute, is better, although in some cases, 
where air is brought into high-studded rooms over eight feet from 
the floor, a velocity of seven feet per second is not objectionable. 

In arranging for an air supply for any system of heating and 
ventilation the number of cubic feet of air to be supplied per 
minute, divided by 300, will give the area in square feet for the 
pipe or flue. 

Uncomfortable drafts will be caused if the air is brought into 
the room at too great a velocity, no matter whether by a gravity or 
a mechanical system. 



52 THE SCHOOL HOUSE. 

Air may be forced through a main supply pipe at a velocity of 
800 or 1,000 feet per minute by a fan, or at even a greater velocity 
by the expenditure of additional power, which, however, is not 
always true economy ; but the risers or ducts leading to the rooms 
should be designed to admit the air into the room at not over 360 
feet average velocity per minute. 

Taking a small riser from the main duct and increasing the area 
at the entrance into the room will not give the best results. 

There should be a steady and certain outflow of vitiated air 
through the extraction flues. It will not do to have back drafts. 
As before intimated, all ducts carrying vitiated air are likely to 
become coated with foul matter. There should be no possibility 
of any return of this matter to the rooms. 

With properly constructed vent ducts or aspirating chimneys there 
need not be a back draft under any conditions of wind or temperature. 

Every building constitutes a problem by itself, to be solved only 
after a careful study of all the conditions presented, and then only 
with a knowledge of the principles of ventilation and heating, and 
the mechanical skill and experience requisite for a practical appli- 
cation of this knowledge to the work in hand. 

Every schoolhouse and public building should be planned with a 
view to a thorough system of heating and ventilation. 

Heating and ventilation are closely connected, and should be 
planned at the same time. 

In the construction of schoolrooms, beams or projections below 
the ceiling should be carefully avoided to prevent the deflection of 
the current of air from the inlet, and to avoid causing uncomforta- 
ble drafts. If beams project down below the ceiling and are at 
right angles to the entering air current the air will be deflected and 
strike the heads of the occupants of the seats a short distance 
below and beyond the beam. If the room is being cooled off or 
the temperature of the entering air is lower than that of the room, 
the uncomfortable drafts will be very apparent. 

If the inlet is between two beams parallel to the direction of the 
current of the incoming air, or between a beam parallel with the 
outer wall and the wall itself, the air will pass along between the 
parallel beams or between the beam and the wall to the outer wall 
opposite the inlet without spreading across the ceiling properly. 
In such cases an undesirable difference of temperature will be noted 
in various parts of the room. 

In high-studded assembly halls, usually placed in the upper story 
of a large school building, it is advisable that additional ventilators 



THE SCHOOL HOUSE. 53 

be placed in the ceiling io carry off an excess of heat or an accumu- 
lation of foul air at the top of the room, which is too high to be 
conveniently ventilated entirely by the vent openings at the floor 
level. These ceiling ventilators are not intended to be used at all 
times, but only as the special occasion may require. They should 
preferably pass up through the roof, or they can be connected with 
the ducts which take the air from the bottom of the room. 

Where gas lights are used the ceiling ventilators should be placed 
over the groups of burners. 

Placing the stacks of indirect radiators or the furnace in the 
basement in a wrong position, at the base of the warm air shaft, is 
a source of cold and uncomfortable drafts in the room. 

The heating apparatus should always be placed in such a 
position thai the warm air will pass up on the front or room side 
of the shaft and the cold air used for mixing will pass up on 
the rear side. If placed so that the warm air comes up on the 
rear side of the shaft cold drafts will surely be felt. 

Deflectors and diffusers, which are generally useless, costly and 
unsightly devices, placed in front of the warm air inlets will not 
prevent these troublesome cold drafts. 

A mixing damper, which is a device placed near the bottom of 
the warm-air shaft to regulate the temperature of the incoming air 
without materially diminishing the quantity, is of great service. 

When it is desired to have an entire supply of warm air the 
chain leading from the mixing damper to the schoolroom is let out, 
and the mixing damper falls back and prevents the entrance of cold 
air into the shaft. When it is desirable to cool the incoming air 
the chain is pulled a little, and cold air is admitted to mingle with 
the warm air in the shaft. 

This damper should not be changed from all warm to all cold, 
or from all cold to all warm air, by one movement. If this is done 
the room temperature maybe too quickly-changed and the room 
made too cold or too warm, and a constant variation of the tempera- 
ture of the air in the room will follow, often accompanied by cold 
drafts in very cold or windy weather. 

When it becomes necessary to change the temperature of the 
room the mixing damper chain should be gradually let out or pulled 
in; about one inch or less at a time will generally be sufficient. 

When the heating apparatus is properly located at the base of 
the warm-air shaft the warm air will pass up on the front and 
the cold air on the rear part of the shaft, the cold air being drawn 
up and mixed by the ascending current of warm air. If the two 



54 THE SCHOOL HOUSE. 

currents are not thoroughly mixed in the shaft before the direction 
of the air currents is changed from a perpendicular to a nearly- 
horizontal direction to flow into the room, the warm air will be on 
the lower side of the stratum of fresh air and will buoy up and 
diffuse the cold air. 

If, however, the cold air is on the front side of the shaft, when 
the direction of the current is changed the cold air will be on the 
bottom of the stratum of fresh air, and being colder than the air 
in the room, will fall as an uncomfortable draft on the occupants of 
the seats in front of the inlet. These cold drafts are usually more 
noticeable at from eight to twelve feet in. front of the inlet than in 
other parts of the room. 

An excessive outflow of air through the outlet duct is not desira- 
ble, as the air currents are sometimes deflected or short circuited, 
and the heat and fresh air are wasted before having done the work 
required in the rooms. 

This is jDarticularly the case in very cold or windy weather. It 
also causes an excessive leakage of cold air into the room, and 
sometimes reduces the temperature of the air in the room to an 
undesirably low point. 

Every foul-air outlet should be provided with a galvanized-iron 
curved damper, or at least a roller-shade curtain, to regulate the 
outflow of air. 

Judgment must be used by the janitor and teacher in the manage- 
ment of these dampers. During mild weather the damper should 
be wide open, but during very windy or cold -weather it should be 
partly but never fully closed while the room is occupied. 

The proper management of these outlet dampers is a matter that 
should be fully and carefully explained to the teachers and janitors. 

In cold weather, when the room is not occupied, the outlet 
dampers should be closed in order to prevent an undue loss of heat 
from the room. While a schoolroom should be thoroughly venti- 
lated during school hours and after the school has been dismissed, 
the outlet damper should be left open long enough to flush out the 
room with fresh air, yet to continue the ventilation the whole 
twenty-four hours will cause an unnecessary expenditure of fuel 
which would be extremely wasteful. 

In some cases gossamer rubber-cloth flap-check valves have been 
placed at the outlet opening. These things are, however, seldom 
used by the most successful heating and ventilating engineers and 
contractors, as they are often -worse than useless. It takes a strong 
current of air to open them, and this means an expenditure of 



THE SCHOOL HOUSE. 55 

power, either mechanical (by a fan) or of heat, which is a need- 
less waste. Being automatic and intended to prevent back drafts 
they are liable to close while school is in session and shut off the 
outflow of foul air, or they may open at night or when the school 
is not in session and cause a loss of heat from the building and an 
unnecessary cooling of the rooms. When a strong wind is blowing 
they often flap open and shut, making a noise which is very objec- 
tionable in a schoolroom. With a properlv designed and located 
vent shaft, having either a fan or heat to cause the outflow of foul 
air, and with a clamper to close when ventilation is not required, 
there should be no use for such worthless and objectionable things 
as gossamer flap-valves in a vent duct. 

Many persons advocate the plenum system, in which the air is 
forced into a schoolroom and the pressure in the room is outward, 
rather than the exhaust system. 

In factories and places where machinery and belts keep the air 
in motion and well stirred and mixed, and where heat is more to be 
considered than the amount of air for ventilation, the plenum system 
is well adapted to the purpose. A hot-blast system which will 
produce excellent results in a factory or large workshop, will not 
give the desired results in a schoolroom. 

In school buildings and audience halls, where a large quantity of 
moderately warmed air is required for ventilation, it has been the 
writer's experience that a judicious combination of the plenum and 
exhaust systems gives the best results. 

Where the plenum system alone is used and no heat or mechani- 
cal means employed for exhausting the foul air, the results have 
not been as satisfactory as where the two systems were combined. 

In the plenum system the air, being under a slight pressure in all 
parts of the room, is forced out, not only at the vent openings but 
through every crack and opening, and the circulation is not as good 
as in a combination system, and a greater amount of heat is required. 

Many heating and ventilating systems would have proven failures 
had it not been for the amount of air supplied by leakage into the 
rooms. 

The writer has found, when measuring the air supply in school- 
rooms, that under certain conditions from 50 to 300 per cent more 
air was going out at the outlet than was coming in at the fresh-air 
inlet, the difference being made up by the inward leakage. In 
many cases where a sufficient supply of air had not been provided 
the pupils would have suffered had it not been for this inward 
leakage of fresh air. Even with such a great difference between 



56 THE SCHOOL HOUSE. 

the air supplied and the air exhausted, the temperature did not vary 
but three or four degrees, as was shown by thermometers placed 
on the pupils' desks at the four corners of the room and also on the 
teacher's desk. 

These differences have been noticed in both the mechanical and 
gravity systems of supply, and are not confined wholly to wooden 
buildings of cheap construction. 

A person not conversant with the facts may well be inclined to 
doubt the correctness of this statement, but a series of careful 
tests will convince him of its accuracy. 

The force and direction of the prevailing winds in the district 
where the building is located should also receive careful considera- 
tion from the heating and ventilating engineer and the architect. In 
Massachusetts the prevailing winds in winter are from the northwest. 

Where air is forced by a fan through a long duct against the 
prevailing winds, and where there are several branches taken off, 
suitable allowance must be made' in the size of the ducts, and at 
each branch where it leaves the main duct suitable adjusting 
switch-dampers or reducers should in all cases be provided. 

Theoretically, the size of the duct to carry a certain amount of 
air at a given velocity to a given point may be easily calculated ; 
but the engineer or architect must not be surprised to find his 
calculation considerably out of the way some day when a cold and 
strong wind is blowing, if the prevailing direction of the wind has 
not been taken into account when designing the system. 

The discharge from a ventilating duct, even when a good fan is 
provided, should never be directly out from the side or end of a 
building, when it can be possibly avoided. The writer has seen 
cases where the discharge has been out from the side of the build- 
ing against a very strong wind, and when a good fan was running 
at a high speed no air would be discharged from the outlet pipe. 
The strong wind blowing directly into the discharge pipe would 
more than neutralize the power of the fan. 

The vent-duct opening should be up and through the top of the 
building whenever possible to have it so placed. 

If on account of the construction of the building it is not 
practicable to carry the vent opening to the top, but is necessary to 
discharge from the side or end, a shield or guard should be pro- 
vided to deflect the wind and prevent it blowing directly into the 
vent opening. 

A strong wind blowing across the top of a chimney or venti- 
lating duct will produce an additional outflow of air. 



THE SCHOOL HOUSE. 57 

To illustrate this action, take a glass tube about three-eighths of 
an inch diameter and about five or six inches long, open at both 
ends ; in the tube, about two-thirds of the distance from the 
bottom to the top when the tube is held in a perpendicular position, 
place a light bit of cotton fibre or similar material, then holding 
the tube before, but not too close to your mouth, give a strong puff 
from the lungs. The cotton will be forced up and out the tube 
and fly off in the direction of the current of air from the lungs. 

To illustrate the effect of wind striking a projection on or near 
the top of the chimney or vent shaft, use the same tube and bit of 
cotton, but hold the hand or some flat article, such as a book or 
piece of board, in front of and beyond the top of the perpendicular 
tube ; a strong puff from the lungs will cause the air to strike the 
obstruction and be deflected down into the tube, carrying the cotton 
out at the bottom. 

It sometimes happens that one vent flue in a school building will 
cause trouble by having a down draft, while the other will be 
doing satisfactory work. If an inspection is made of the top of 
the flue it will probably be seen that some projection is above or 
against one side or end of the top, against which the wind strikes 
and is deflected down the vent flue. 

The practice of extending the smoke flue up above the level of 
other parts of the same stack should be avoided. Unless 
absolutely called for by some special construction of the building 
as regards towers, etc., the top of the smoke and vent flues, if 
constructed of masonry, should not be capped or hooded over. 
The danger of water or snow going down the brick flue is very 
small. The bricks, being porous, absorb the moisture, which is 
soon evaporated 'by the current of warm, dry air passing up the flue. 

Vent flues and chimneys should when practicable be carried well 
above the highest part of the ridge. 

The writer recalls a building designed by a well-advertised firm 
of architects in which the system of heating and ventilation was 
designed by a heating and ventilating engineer who has frequently 
been quoted as an expert. * 

The vent shaft was of large dimensions ; in it were the venti- 
lating openings from several rooms, and there were no divisions or 
withes in the shaft. The top was considerably below the ridge of 
the building, and was capped with blue-stone flagging. There 
were two good-sized openings on each side under the cap. 

A considerable quantity of steam-pipe was placed in a coil 
around the sides of the shaft and located just above the floor of the 



58 THE SCHOOL HOUSE. 

first story of the building. Flap valves were placed over the room 
outlets to prevent hack drafts. When the wind was from a certain 
direction these flap valves were kept closed by the down drafts, 
thereby shutting off the ventilation from the schoolrooms. 

Complaints of bad ventilation continued to be made. More 
steam pipes were put in the shaft till about 300 square feet of radi- 
ating surface had been put in the shaft. 

The complaints continued, and the writer was called by the 
school authorities to see what was the trouble. The examination 
was made on a cold day when a strong wind was blowing. The 
steam was turned on full head in the vent-coil heaters (the boiler 
pressure being ten pounds by the gauge) . 

Commencing in the basement at the lowest opening into the 
vent shaft, the flap valves were found to be closed, and on lifting 
them and placing an anemometer in front of the opening so made, 
the air was found to be coming down and into the room at a 
velocity of over 500 feet per minute and at a temperature of 28 
degrees F. , 

The school authorities were advised to remove the blue-stone 
cap, brick up the openings in the shaft, and carry it above the 
ridge; also to remove the flap valves. This was done, although 
the architects protested that it would injure the architectural 
appearance of the building. Galvanized iron dampers were placed 
at the room outlets where the flap valves had been removed, and 
part of the steam-pipe was taken out of the shaft. 

No trouble was afterward found in having a good outflow of foul 
air from the schoolrooms, and no back drafts were noticed. 

Where galvanized iron vent flues are used it is well to cover them 
with a cap which should project well beyond the sides of the duct. 
It is essential that sufficient clearance space be allowed between the 
cap and the top of the vent flue. How frequently we see flues of 
ample size that have a cap close down to the top of the flue with 
but little chance for the air to escape. 

It should be remembered that the openings on all four sides are 
not always available, and that only about one-half of the area can 
be considered as effective, that is, the leeward half, or the part in 
the direction the wind is going. 

Whether the warm-air inlets and foul -air outlets are properly 
located can be determined by wrapping in a piece of paper dipped 
in nitrate of potash and then dried, or in a piece of tissue paper, a 
small tablespoonful of gunpowder, placing it on a piece of sheet 
metal or board held about two feet in front of the warm-air inlet, 



THE SCHOOL HOUSE. 59 

setting fire to the paper and watching the circulation and diffusion 
of the smoke. 

A sponge saturated with ammonia and held over a dish of hydro- 
chloric (muriatic) acid will also show the circulation of air, but 
is not as convenient or desirable as the powder smoke test. 

The down or coma of the milkweed or thistle can also be used 
to show the movement of air currents in a room, but not as fully 
as the powder smoke test. 

The movement of the air currents by the powder smoke test may 
be best observed by taking a position at the inner angle of the 
room, so selected that the light from the windows in the outer 
walls wall best enable the observer to see the movement of the 
smoke. 

The action of open windows on the circulation of air in a room 
will become apparent by using the powder smoke test. 



CHAPTER IV. 



AIR SUPPLY FOR SCHOOL ROOMS. 

THE following tables give the average results of a number 
of tests of the air supply in schoolrooms made by the 
Massachusetts inspectors in different parts of the state 
in buildings of different size and construction, of wood or brick, 
under different conditions of temperature, wind, weather, humidity 
and barometric pressure. 

These results are not to be considered as what is theoretically 
required, but such as may be expected in actual practice in school- 
house ventilation. 

The inside temperatures were taken at the breathing plane, at 
the four corner desks and at the teacher's desk at the same time. 



TABLE 3. 
Average Results of Tests Made in 100 Ventilated Schools. 



Temperature, Degrees F. 


Velocity at Inlet, 
Feet per Minute. 


Net Available 
Area of Inlet, 
Square Feet. 


Cubic Feet of Air 


Outside. 


Inside. 


At Inlet. 


Per Minute 
Supplied at Inlet. 


34.26 


69.69 


93.78 


399.39 


4.439 


1,772.892 



TABLE 4. 

Average Results of Tests Made in 500 Ventilated Schools When 

Outside Temperature was Below 40° F. (Fractions Omitted 

in this Case.) 



Temperature, Degrees F. 


Velocity at Inlet, 
Feet per Minute. 


Net Available 
Area of Inlet, 
Square Feet. 


Cubic Feet of Air 


Outside. 


Inside. 


At Inlet. 


per Minute 
Supplied at Inlet. 


25 


70 


92 


377 


4 


1,508 



THE SCHOOL HOUSE. 



61 



TABLE 5. 
Average Results of Tests Made in 500 Ventilated Schools. 



Temperature, Degrees F. 


Velocity at Inlet, 
Feet per Minute. 


Net Available 
Area of Inlet, 
Square Feet. 


Cubic Feet of Air 


Outside. 


Inside. 


At Inlet. 


per Minute 
Supplied at Inlet. 


40.01 


70.6 


933 


355.4 


4 


1,421.0 



TABLE 6. 
Average Results of Tests in 1,040 Ventilated Schools. 



Temperature, Degrees F. 


Velocity at Inlet, 
Feet per Minute. 


Net Available 


Cubic Feet of Air 


Outside. 


Inside. 


At Inlet. 


Area of Inlet 
Square Feet. 


per Minute 
Supplied at Inlet. 


37.9 


70.2 


93.3 


369.6 


4.13 


1,526.488 



These tests show the amount and temperature of air supplied at 
the warm-air inlets, but do not include the additional amount of air 
brought into the room by leakage through walls, ceilings, floors, 
or through openings or cracks around doors and windows when 
the exhaust through the vent shafts was greater than the supply at 
the warm-air inlets ; neither do they take into consideration the air 
forced out of the room through the same places when the conditions 
are reversed and the supply at the inlets exceeded the exhaust at 
the vent openings. 

In some cases the air exhausted through the vent ducts was con- 
siderably in excess of the supply at the inlets, the difference being 
made up by inward leakage. In other cases it was the reverse, 
and outward leakage accounted for the difference. 

These are average tests, and do not include those cases where a 
great difference was found between the amount of air supplied at 
the warm-air inlet and that extracted at the vent outlet. Sometimes 
the amount of air is more than double at the outlet the amount at 
the inlet, or it may be the reverse. 

These cases occur in loosely-constructed buildings, or where 
proper adjustment has not been made of the dampers at the outlets 
or of the windows admitting ;iir to the cold-air rooms where the 
indirect radiation is located. They are only mentioned to show 
the necessity of good construction and proper regulation of the 
exhaust and supply openings. 



62 



THE SCHOOL HOUSE. 



From a large number of observations it appears that in order to 
supply a schoolroom with 1,500 cubic feet of air per minute when 
the temperature outside is 30 degrees F. we shall have to introduce 
the air at the warm -air inlet at about 93 degrees F. to keep the 
room at 70 degrees F., at the breathing plane of the pupils, raising 
the temperature of the air 63 degrees F. Fifteen hundred cubic feet 
of air raised 63 degrees equals 94,500 cubic feet raised one degree. 

From the average tests of a large number of unventilated schools 
we find that to keep a schoolroom at 70° F. with the outside 
temperature at 30° F., supplying 500 cubic feet per minute, we 
shall have to send the air in at about 180° F. This is an increase 
of 150 degrees over the outside air. 

Five hundred cubic feet raised 150 degrees equals 75,000 cubic 
feet raised one degree. 

Assuming that it costs the same in each case to raise a cubic foot 
of air one degree in temperature, the increased cost of furnishing 
1,500 cubic feet per minute to a schoolroom over the old method 
of furnishing 500 cubic feet per minute would be about 26 per cent 

The cost of heating schoolrooms varies considerably in actual 
practice, depending upon the construction and location of the 
building, the system of heating and ventilation installed, and the 
care and judgment exercised by the janitor. 

A fair average allowance of fuel for good ventilation and proper 
warming may be considered as ten tons of hard coal per school- 
room per year. This includes all the space within the building 
occupied by corridors, basement and small rooms, in addition to 
the schoolrooms. 

The following shows the cost of heating eight schoolhouses by 
different methods during the winter of 1893 and 1894, and is 
given as showing the difference in cost that may occur under 
different conditions. 

TABLE 7. 





Kind of 




Number of 


Cost of Fuel 


Building. 


Heat. 


Ventilation. 


Rooms. 


per Room. 


1 


Steam 


Combination of supply and exhaust 


10 


$50.50 


2 


Steam 


Combination of supply and exhaust 


16 


53 31 


3 


Steam 


Plenum supply, no special exhaust 


22 


106.00 


4 


Steam 


Plenum supply, no special exhaust 


12 


108.10 


5 


Furnace 


Combination of supply and exhaust 


12 


60.75 


6 


Furnace 


Combination of supply and exhaust 


8 


63.25 


7 


Steam 


No modern ventilation 


16 


90.82 


8 


Furnace 


No modern ventilation 


13 


63.53 



THE SCHOOL HOUSE. 63 

Warm-Air Ducts or Flues. 

The proper location of warm-air inlets for supplying fresh air to 
schoolrooms is a matter that should be carefully considered by the 
architect who plans the building and also by the heating and venti- 
lating engineer who designs the system ofi heating and ventilation. 
This is also referred to under the head of circulation of air. The 
size or cross-section of the warm-air duct is another subject for 
careful consideration, and is determined by the amount of air to 
be supplied, and should be proportioned to the number of persons 
who are to occupy the room. 

One of the defects in the early attempts at ventilation was the 
small area of cross-section of the warm-air supply ducts. With 
the gravity system, when too small ducts were used, it was 
necessary that the air be heated to a very high temperature in order 
to give the required velocity to obtain the amount desired. 

In a mechanical system, where a fan is used and J:he ducts are 
not large enough, the air will be forced into the room at too great 
a velocity, sometimes causing uncomfortable drafts. The fan will 
also require additional power in order to force the air through the 
small ducts at high velocity. 

In a gravity system, the warm-air ducts should be of ample area 
to admit the air in sufficient quantity to meet the requirements of 
mild weather when it is only warmed to a moderate degree. 

iMany tests by the Massachusetts inspectors show that the best 
results are obtained when the warm-air ducts have a cross-sectional 
area of 24 by 36 inches (six square feet). 

Five square feet, 24 by 30 inches, will give fair results, but 24 
by 36 inches is to be preferred. This is for an ordinary school- 
room 28 by 32 by 12 feet, accommodating 50 persons. 

Class-rooms a little larger or smaller than the above standard, or 
containing a greater or less number of persons, can have the warm- 
air ducts proportionally increased or diminished. In small rooms, 
or in large rooms having but few pupils, or where there is a large 
exposed wall or glass surface, or where no direct radiation is used, 
a liberal allowance should be made -for the area of the warm-air 

ducts 

The top of the warm-air duct, where it enters the room, should 
be curved to easily change the direction of the entering air from a 
perpendicular to a nearly horizontal direction. The interior of 
brick warm-air and foul-air ducts ami Hues should be made as 
smooth as practicable, and rough projections of mortar should not 
be allowed. Where the expense can be incurred it is advisable to 



64 THE SCHOOL HOUSE. 

cover the inside walls of warm-air ducts with a light coat of 
adamant plaster or Portland cement to give a smooth surface and 
reduce the^friction. 

Galvanized-iron ducts should be made as tight as practicable. 

Ducts constructed of laths and plaster, or of expanded metal 
and plaster, should not be used, as the leakage of air through them 
is very great. 

The inlet opening into the room should be of larger area than 
the cross-section of the uptake duct in order to allow for the 
obstruction of the register face or grill covering the opening, and 
also to allow for the space at the bottom of the opening where 
there is little, if any, inflow of warm fresh air. 

If a wire grill is used to cover the opening into the room the 
opening should be at least 30 by 36 inches where the uptake is 
24 by 36 inches. 

Where cast-iron register faces are used the opening should have 
an area of from 33 to 50 per cent larger than the uptake, on 
account of the reduction of the available area and the friction of 
the register face. Cast-iron register faces are more expensive than 
wire grills, and, when placed above the floor level, cannot be 
recommended for covering warm-air inlets or foul -air outlets. 

When two or more stories of the same building are to be 
, supplied with warm air from the same source, and where the ducts 
all lead from one cold-air room, it is well to place the duct for the 
first story nearest the cold-air supply window. The first story 
duct, being of less height than the others, will have less lifting 
power than those to the second and third stories, and, consequently, 
should be placed where the supply is largest, especially if the cold- 
air room or duct to the heater is of limited capacity. If the duct 
leading to the second or third story is placed nearest the source of 
supply, being higher or longer than the one leading to the first 
story it will rob that duct of its fair proportion of air. 

The opening in the duct where it receives the warm air from the 
heaters should be but a few inches above, or, better, on the level 
with the top of the indirect radiators or directly from the hot-air 
chamber of the furnace. 

The opening for receiving the cold air for mixing and reducing 
the temperature of the warm air should be at the bottom of the 
duct and of an area equal at least to the cross-sectional area of the 
uptake duct. 

The mixing damper for regulating the temperature should be 
hung at the bottom of the warm-air opening from the heater, and 



THE SCHOOL HOUSE. 65 

should incline upward toward the back of the duct. It should be 
operated from the schoolroom by means of a stout chain and suitable 
device for holding it in any desired position. 

It is advisable in many cases to provide a sliding adjusting dam- 
per at the bottom of the opening where the warm air from the 
heater enters the uptake duct, in order that the supply of air to the 
different rooms may be properly adjusted. 

Theoretically, the warm-air ducts leading to the upper rooms 
may be of less cross-section than those leading to the first story. In 
actual practice this is seldom done, and the adjusting damper or 
slide is used. 

When a mechanical system is used and the air to the several 
rooms is forced by a blower or fan through one or more main 
supply ducts, and branches are taken off for the different rooms, a 
switch or adjusting damper should always be provided at the point 
where the branch leaves the main duct, and suitable means pro- 
vided for holding the switch damper in any desired position. 

The cross-sectional area of each branch and the reduction of area 
in the main duct as the branches are taken off should be calculated 
theoretically, making proper allowance for friction, but the switch 
dampers should never be omitted if proper distribution of air to the 
several rooms is expected in actual practice. 

The writer has never seen entirely satisfactory results obtained 
under all conditions of wind and temperature where the switch 
dampers have been omitted, although the sizes of the different 
branches had been carefully designed according to the best theo- 
retical rules. If a very strong north or northwesterly wind was 
blowing, the switch dampers could be adjusted to meet the existing 
conditions ; but if the wind was from the south or southeast a 
different adjustment of the switch dampers would be required. 

Where a fan or blower has been used and the ducts had not been 
designed of suitable size and the air entered the room at too high 
a velocity, causing uncomfortable drafts, the writer has in some 
cases to a considerable extent overcome the difficulty by placing 
inside and against the grill a* wire screen made of ordinary iron 
mosquito netting. Where this is used the grill should be arranged 
so that it can be easily taken out to clean the screen occasionally. 

Although this screen will be an obstruction and require a little 
more power, yet it is better than to have the uncomfortable drafts. 

This mosquito-screen netting should only be used where a 
mechanical (fan) system is in operation, and should not be used 
with a gravity system. 



66 THE SCHOOL HOUSE. 

Aspirating Chimneys and Vent Flues. 

The power of an aspirating chimney or vent flue to remove a 
given quantity of air from a room depends upon its area or cross- 
section, its height, the difference between the external and internal 
temperature, the resistance or friction, and also the admission into 
the room of a sufficient quantity of air to replace that removed by 
the aspirating shaft. 

The suction caused by a strong wind blowing across the top of 
the chimney is another important factor, but on account of its 
uncertainty is seldom taken into account in theoretical calculations. 

To increase the velocity of the flow of air through an aspirating 
chimney or flue we must either increase the height of the chimney 
or raise the temperature within the flue. 

As increasing the height of the chimney has the same effect as 
increasing the temperature in the flue, we see the advantage of 
having the chimney as high as practicable. The increased height 
costs nothing after the chimney is built, while the increase in heat 
is a constant expense. 

In school buildings, for architectural reasons the aspirating chim- 
ney should not be too high, consequently we raise the temperature 
of the air in the chimney by means of heat applied there, or when 
a mechanical (fan) system of ventilation is used the air is forced 
out by means of a fan. Air expands about 1/490 of its volume for 
each degree of increase in its temperature, and, consequently, 
decreases in weight per cubic foot as its temperature is raised. 

The heated column of air in the chimney, being lighter than a 
column of external air of the same area and height, rises, being 
forced up by the greater weight of the external air. 

To find the theoretical velocity in feet per second of air in a 
ventilating chimney : 

Let t = temperature of the external air ; t x = temperature of 
the air within the chimney ; T = absolute * temperature of the 
external air; H = height of chimney in feet, and V = velocity 
in feet per second ; 



Then V = 8.02 -J H (*i ~ 
T 

By multiplying the value of V by 60 we have the theoretical 
velocity in feet per minute. 

The theoretical velocity cannot be obtained in actual practice, 
and a deduction of from 30 to 50 per cent (for roughly built and 

* Absolute temperature = 460 degrees below zero. 



THE SCHOOL HOUSE. 67 

crooked flues even more) should be made from the theoretical 
velocity for friction and eddies. 

Neglect to make sufficient allowance for friction in ducts and 
aspirating chimneys has been the cause of partial failure in many 
an otherwise well-arranged scheme of ventilation. 

Care should be taken that an aspirating chimney is not too large 
or too small. 

In the small chimney the friction may be the cause of failure, 
and in one too large, eddies will contribute to the same result. 

By standing in the bottom of an abnormally large aspirating 
chimney and throwing into the different parts of the chimney 
thistle-down or coma of the milkweed, the action of the eddies can 
easily be seen by watching the movement of these light substances. 

It is better to provide a separate vent duct from each room than 
to enter the vents from several rooms into one large aspirating 
chimney, as the outflow of air from the several rooms can be more 
easily and equally regulated where separate vent ducts are provided. 

The amount of heat required for each flue and the position of 
the damper can then be regulated to meet the special requirements 
of each room, especially when there is a strong wind. 

At one time a very common method of heating an aspirating 
chimney or flue was by placing the smoke-pipe from the furnace in 
the center of the chimney, a cast-iron pipe being sometimes used ; 
occasionally one made of drain-tile. When we consider the low 
temperature at which the products of combustion should enter 
such a pipe from a well-designed furnace, and the fact that the 
smoke-pipe was placed in the most effective and best part of the 
vent shaft, as well as the large increase in friction, it may well be 
doubted whether much was gained by this process. 

Furthermore, such a pipe was of no use in mild weather, when 
there was no fire in the furnace or stove. In mild weather more 
heat is required in the aspirating chimney than when the outside 
temperature is low. 

When several rooms are vented into one common vent shaft there 
will frequently be an excessive outflow from one room, while it 
may be deficient from others. 

In one large vent shaft there are more likely to be eddies and 
counter currents than where several smaller vent flues are used. 
When the ventilation of several rooms into one large shaft is 
attempted, the location of the steam-pipes or radiators will some- 
times be a rather difficult matter in order to obtain uniform and 
economical results from the different rooms. 



68 THE SCHOOL HOUSE. 

When, however, no steam-pipes or radiators are provided in the 
vent shaft and a stack heater or small stove is installed, as is the 
case in many school buildings where furnaces are used, the large 
common vent shaft or aspirating chimney becomes a necessity. 

In such cases the ventilation from the lower rooms is through 
register openings in the floor, and the foul air is taken down to the 
bottom of the basement and enters the common shaft below the 
" stack heater " 

The air taken down from the lower rooms, being heated by the 
stack heater in the common shaft, rises, forced up by the denser 
air on the outside. 

A damper should always be provided in these ducts leading from 
the first story rooms to the bottom of the common vent shaft. 

If the ventilation from the second story rooms enters directly 
into the common shaft and a curved damper as a deflector is pro- 
vided at the vent openings from the second story rooms, the ascend- 
ing air, in passing the curved damper or deflector, will cause an 
induced current from the second story rooms into the common vent 
shaft, on the same principle as that of the steam siphon often used 
in removing bilge -water from vessels propelled by steam. 

Many tests have shown that when this system is used the velocity 
of the foul air from the second story rooms is greater than from the 
first story, and sometimes it will be necessary to use the damper to 
check the outflow from the second story. 

The only advantage in taking the foul air from the first story 
rooms down to the bottom of the common vent shaft is to have the 
stack heater placed conveniently near the other heating apparatus, 
and to avoid the dust and dirt which would be caused by placing 
the stack heater above the vent opening directly from the lower 
rooms into the common shaft. 

If the air in the first story schoolrooms is 70 degrees F., and the 
air in the common vent shaft has been raised to 85 degrees F. by 
the stack heater in the lower part of the common shaft, only 15 
degrees of heat are available as a motive force in the shaft at the 
level of the first story floor to overcome the friction and also to 
cause an outflow of air in the shaft at that level — 70 degrees being 
required to establish an equilibrium between the down and up 
ducts at that level. Above this level we have the advantage of 
the height of the column of warm air between the first and second 
stories. 

The stack heater should ahvays be placed above the point where 
the down ducts from the first story enter the common shaft. 



THE SCHOOL HOUSE. 69 

When the stack heater is placed below this point a very large 
waste of fuel takes place, and satisfactory results will not be 
obtained. 

When the stack heater is placed opposite the opening in the shaft 
where the down duct enters, a considerable quantity of heat is radi- 
ated into the down duct and offsets an equal amount of heat in the 
common shaft. 

The air should pass up by and close to the heated surface of the 
stack heater to produce the best results. 

In placing the stack heater in the vent shaft it should be so located 
that the air for the combustion of the fuel and the draft for the 
heater are taken from outside the vent shaft. 

In some of the earlier attempts at ventilation by using the stack 
heater in the vent shaft, the heater was placed entirely within the 
shaft and a manhole door was provided, through which to tend the 
heater. This arrangement did not give satisfactory results, as the 
supply of air for the combustion of the fuel was considerably lessened 
by the suction of the current of air passing up all around the hot 
surface of the fire-pot and reducing the draft through the grate, in 
some cases causing the fire in the stack heater to go out before the 
fuel was consumed. 

The practice of bringing a number of vent ducts together in one 
common chamber in the attic of a schoolhouse, and placing in this 
chamber a quantity of steam-pipes, is not to be recommended. It 
is much better and more economical to place the heating surface in 
the separate ducts and about one foot above the top of the vent 
opening from the room. In the first case we have only the lifting 
power of a column of warm air from the level of the steam-pipes 
in the chamber in the attic to the top of the vent stack, while in the 
latter case we have the lifting power of the longer column of warm 
air from the level of the radiating surface just above the opening 
at the schoolroom floor to the top of the vent stack, or, in other 
words, it would be a low chimney instead of a high one we depended 
upon to do the work. 

A considerably less amount of heat will be required in the tall 
chimney than in the short one. 

More even removal of foul air from the several rooms will be 
obtained when using separately heated vent ducts than when the 
common chamber in the attic is used. 

When an exhaust fan is used, it is advisable to bring the separate 
vent ducts into one common chamber in the attic where the fan is 
located, and to control the flow of air from the several ducts into 



70 THE SCHOOL HOUSE. 

the common chamber by a properly arranged adjusting damper in 
each duct. 

Theoretically, we can calculate the amount of air each separate 
duct should remove, but in actual practice the theoretical results 
will seldom be obtained, on account of the constantly varying con- 
ditions of external temperature and wind ; consequently, means for 
adjusting the outflow from each separate duct must be provided. 

In actual practice 20 square feet of steam radiation surface in the 
vent flue from an ordinary fifty-seat schoolroom (28x32x12 feet) 
placed about one foot above the opening from the schoolroom, will 
give satisfactory results when the flue is straight and well built and 
when the vent flue has a cross-section of five square feet area (24 x 
SO inches). If it becomes necessary for architectural reasons to 
carry a vent duct nearly horizontally for any considerable distance, 
either under the floor or over the ceiling, before it enters the per- 
pendicular flue, this amount of radiation may be increased. 

Better results are obtained when the steam-pipes or radiators are 
placed with the lower part at the back of the vent flue and are 
inclined up and toward the front, than when an equal amount of 
radiating surface is placed around the sides. 

The supply and return steam-pipes for supplying the vent-flue 
radiation should be placed at the back of the flue. If placed on the 
front side they will prevent the dampers being properly opened. 

Where vent -flue heaters are made of steam-pipes, one-inch or 
one-and-one-quarter-inch pipes should be used and spaced so that 
they will cover the whole horizontal distance from one end to the 
other of the vent duct. 

Where cast-iron radiators are used it is better to use radiators 
which are thin and wide and about 45 inches long (5 square feet 
per section) , and space them with long nipples so that they will 
be evenly distributed across the full length of the duct. Do not 
use extended surface radiators in a vent duct, on account of the 
friction of the air passing over the projecting surfaces. 

For the ordinary fifty-seat schoolroom (28 x32 x 12 feet) a vent 
flue 24x30 inches or 5 square feet, one square foot to each ten 
persons, has been found to be sufficiently large. A larger flue 
than this is not required, and in some cases has been found to be 
detrimental. 

The opening should be at the floor level and should be longer 
than it is high; that is, the length should be 30 inches and the 
height 24 inches. A curved galvanized-iron damper operated with 
a chain and catch should be provided in all cases. 



THE SCHOOL HOUSE. 71 

The proper location of vent openings is described under the head 
of " circulation of air." 

Chimneys. 

In designing a heating and ventilating plant it is of the utmost 
importance that the chimney should be of suitable size to furnish 
a good draft, as on the ability to maintain a good fire depends the 
successful generation of heat. 

In many cases an otherwise well-designed plant has proved a 
failure because the chimney has not been of sufficient size to furnish 
suitable draft for the boilers or furnaces. 

The architect who designs the building, as well as the heating 
contractor, should see that the chimney is properly designed and 
located. 

The location of the chimney should be carefully considered, 
care being taken that the top is a sufficient distance above the 
highest point of the ridge, and that it is not placed in a position 
where the wind will strike on towers or projections and be 
deflected down on the top of the chimney in a manner that will 
destroy the draft, or, as in some cases, cause a reverse draft. 

The writer has in a number of cases been called upon to remedy 
this defect, which would not have occurred had proper precautions 
been taken when the building was planned. 

Under some conditions the action of the wind against a tower or 
roof has been such as to fill the boiler-room with gas, which, 
escaping through an open door in the boiler-room, has passed up 
into the building in a quantity sufficient to make the rooms above 
anything but comfortable or healthful. 

Different writers give different rules for the size of chimneys. 

One formula is : Let H = height of chimney, T = temperature 
of air entering chimney, / = temperature of air at top of chimney, 
and V = velocity in feet per second. Then V= 35.5 ^H (T — /) 

A rule sometimes used is to allow one-eighth the area of the 
grate surface for area of chimney. This rule does not make any 
allowance for the varying heights of chimneys and is of doubtful 
utility. 

Another rule is : Multiply the nominal horse-power of the 
boiler by 112 and divide the product by the square root of the 
height of the chimney in feet. The quotient will be the required 
area in square inches at top of chimney. 

William J. Baldwin gives as a rule: "Having the cubic feet 
of air to pass through a building in an hour, and warmed 100° F., 



72 THE SCHOOL HOUSE. 

and requiring the chimney 100 feet high, divide by 500,000 and 
the answer is in square feet of cross-sectional area." 

Thomas Hawley, late State Inspector of Boilers and Examiner 
of Engineers, and now principal of the " Hawley School for 
Engineers," used the following rule, which appears to be a safe 
one to follow : 

" Make a chimney 81 feet high and of an area equal to the 
collective area of the boiler tube openings. If the chimney is 
higher than this, reduce the area in proportion as the square root 
of the height exceeds the square root of 81." 

To find area of chimney, multiply the collective area of boiler 
tube, openings by 9 and divide by the square root of height of 
chimney. 

These last two rules are based upon the commercial H.P. and 
the evaporation of 30 pounds of water per hour. The coal to be 
burned is figured on this assumption, which is useful in determin- 
ing whether 1 ' the chimney is large enough, as in designing a new 
one, and maybe used when either the area or the height is first 
settled upon arbitrarily, as is often the case when the architect 
designs a building with the chimney a given height above the ridge. 

For larger powers the chimney should be higher than 81 feet, 
in which case the area can be less than the combined area of the 
boiler tube openings. 

For ordinary schoolhouses two stories high, or two stories with 
a hall above the second story, where the area of the chimney is 
equal to the combined area of the boiler tube openings, satisfactory 
results have been obtained, and this may be considered a safe rule. 

A chimney with too large a cross-sectional area may be the 
cause of poor draft as well as one of too small area. 

The height of a chimney is figured from the boiler grate to the 
top. 

The intensity of the draft depends upon the temperature in the 
flue and the height of the chimney, and the amount of air moved 
is controlled by the area of the chimney. 

The amount of air moved will vary directly with the area of the 
chimney for a given velocity of flow ; but the velocity of flow 
increases only as the square root of the height. 

Doubling the height of a chimney only adds one-half to its draft 
power. 

A square chimney is of no more effective size than a round 
chimney of equal diameter ; that is, it is only equal to the area of a 
circle inscribed within the square. 



THE SCHOOL HOUSE. 73 

The friction of a column of air is figured to take an area from 
the chimney equal to the area all around two inches from the sides. 

This should be considered in designing a small high chimney. 

Within the limits of boiler practice the influence of temperature 
on a chimney draft is very small. It makes but seven per cent 
difference whether the temperature in the chimney is 300° or 
550° F. 

The space occupied by a pound of air increases rapidly with an 
increase of temperature, and as the velocity with which it moves 
out of the chimney does not increase as fast, the bulk increases 
faster than the ability of the chimney to handle it ; consequently, a 
temperature is reached at which the amount of air moved cannot 
be increased by that chimney. 

A chimney that tapers at the top has its efficiency decreased. 

A cap on the top of a chimney very materially decreases its 
efficiency. 

A chimney flue should be as straight and as smooth on the inside 
as practicable. 

All connections between the chimney and boiler or furnace 
should be made as straight and short as possible. 

In designing a chimney it should be remembered : That the 
work a chimney will do should be compared upon the pounds of 
air it will handle. 

The space occupied by a certain weight of gas increases directly 
as the absolute temperature. The absolute temperature is 460° 
added to the temperature shown by a Fahrenheit thermometer. 
The absolute temperature of the freezing point is 32 + 460 = 492. 

Increasing the temperature and bulk makes the air in the 
chimney lighter in weight and increases the difference in the 
weight of the column inside and a column of equal sectional area 
outside, and makes a higher column of the lighter air necessary to 
balance a given column of the colder air. 

The difference in . height of the two columns gives the air 
velocity due to this height. The difference in the height of the 
two columns is the moving force. Multiplying the difference in 
height of the two columns by 64.4 and extracting the square root 
will give the velocity. 



CHAPTER V. 



BOILERS. 



A HEAT unit or British thermal unit (B.T.U.) is the 
amount required to raise the temperature of one pound 
of water one degree Fahrenheit (from 62° to 68°). 

A foot pound is the unit of work done, and is one pound lifted 
one foot. 

A heat unit, B.T.U. , is capable of doing 772 foot pounds of 
work. 

Power is the rate at which an agent can do work, and is the 
product of force, distance and time. 

The unit of power is the horse-power (H.P.) and is the doing 
of 33,000 foot pounds of work in one minute. 

The commercial horse-power of a boiler, as adopted by the 
American Society of Mechanical Engineers, is the evaporation of 
30 pounds of water per hour from a feed-water temperature of 
100° Fahrenheit into steam at 70 pounds gauge pressure, which 
may be considered to be equal to 34£ units of evaporation ; that is, 
equal to 344 pounds of water evaporated from a feed-water tempera- 
ture of 212° Fahrenheit into steam at the same temperature, and is 
equal to 33,305 B.T.U. per hour. 

Section 83 of Chapter 102 of the Revised Laws of Massachu- 
setts, relative to the licensing of engineers and firemen, is as fol- 
lows : 

" The horse-power of a boiler shall be ascertained upon the 
basis of three horse-power for each square foot of grate surface, 
for a power boiler, and on the basis of one and one-half horse- 
power for each square foot of grate surface, if the boiler is used 
for heating purposes exclusively. The engine power shall be 
reckoned upon a basis of a mean effective pressure of forty pounds 
per square inch of piston for a simple engine ; fifty pounds for a 
condensing engine ; and seventy pounds for a compound engine, 
reckoned upon area of high pressure piston." 

A pound of coal when properly burned gives from 13,000 to 
14,000 B.T.U. In actual practice, however, only 40 to 50 per 
cent of this is obtainable as effective i'n furnaces. 



THE SCHOOL HOUSE. 75 

In good mill practice one pound of coal, when well burned, will 
give from 8,000 to 9,000 B.T.U., and 12 pounds of hard coal 
burned per hour per square foot of grate surface is considered 
ordinary practice. 

In schoolhouses and public buildings about nine pounds of hard 
coal burned per hour per foot of grate surface may be considered 
the maximum, while six pounds is about the average ; in some 
cases it is as low as four pounds. 

Different heating and ventilating engineers vary as to the amount 
of air that can be raised one degree F. by one B.T.U., the amount 
ranging from 48 to 59 cubic feet. A safe rule, however, is to 
consider one B.T.U. as capable of raising 50 cubic feet of air one 
degree F. 

In designing a heating and ventilating system for a schoolhouse 
or public building it is necessary to ascertain how much air is to 
be supplied for the proper ventilation of the several rooms and 
corridors ; how much heat will be lost from the building by con- 
duction through exposed surfaces, such as walls and windows, in 
addition to that lost by ventilation, and how much heat will be 
required to maintain the desired temperature within the building ; 
in a steam plant, bow much steam will be condensed to maintain 
the desired temperature, and how much radiating surface will be 
needed to condense the required amount of steam ; 

How much coal will be required to be burned to produce the 
necessary amount of steam ; 

How much coal is to be burned per foot of grate surface, and 
how much heating surface must be provided in the boilers to 
generate the desired amount of steam. 

Having determined the amount of coal to be burned per hour to 
properly heat the building, the size of the boilers can then be 
determined. 

The size of grate is an important matter. It is seldom advis- 
able to make a grate more than six feet long. When longer, 
the rear part is liable to be neglected, or the door left open 
•long enough to produce a loss of heat by the large amount of 
air admitted, and also possibly causing an injury to the fire 
sheets. 

The grate should be equal in width to the diameter of the boiler, 
and with its area made up as much as possible by width rather 
than length. 

The ratio of grate surface to heating surface usual in different 
classes of boilers may be considered as follows : 



76 



THE SCHOOL HOUSE. 
TABLE 8. 



Type of Boiler. 


Grate Surface. 


Heating Surface. 


Horizontal tubular, burning soft coal 
Horizontal tubular, burning hard coal 
Upright tubular, burning soft coal 
Upright tubular, burning hard coal 
Water-tube, burning soft coal 
Water-tube, burning hard coal 
Locomotive, burning soft coal 


1 
1 
1 
1 
1 
1 
1 


40 to 45 
30 to 35 

35 

30 
50 to 60 
35 to 40 
35 to 60 



In cast-iron boilers it will vary from 1 to 30 down to 1 to 10, 
according to the design of the boiler. 

In schoolhouse work, with horizontal multitubular boilers burn- 
ing soft coal, 1 to 35 may be considered safe practice ; with hard 
coal 1 to 30. 

The relation that the size of die tube bears to the grate surface, 
and also the number of tubes, have considerable influence upon the 
economy of a boiler. With different coals a different tube opening 
is necessary. On account of the large volume of gases which are 
generated in burning a pound of soft coal, a larger flue area is 
needed to carry them off and prevent the draft being choked. 
With hard coal a less volume of gas is produced and a smaller 
flue area is required. 

The ratio of the grate to the combined area of the tube openings 
may be fixed as follows : 

TABLE 9. 



Type of Boiler 


Area of Grate. 


Area of Tube 
Opening. 


Horizontal tubular, burning soft coal 
Horizontal tubular, burning, hard coal 
Upright 


7 
9 

7 


1 

1 

1 



For horizontal tubular boilers up to 48 inches diameter it is 
advisable to use tubes 2£ inches diameter; from 48 to 60 inches, 
3 inch tubes ; from 60 to 72 inches, 3J inch tubes. 

When figuring the heating surface of a horizontal tubular boiler 
the inside area of the tubes should be taken and not the outside, as 
with a water-tube boiler. 

As upright tubular boilers are used in but a small number of 
school buildings in Massachusetts, their dimensions are not 
given here. 



- THE SCHOOL HOUSE. 77 

TABLE 10. 

Table of Standard Boiler Tubes for Horizontal Tubular 

Boilers. 



Outside Diameter. 


Heating Surface 
per foot in length. 


Area of 
Tube Opening. 


Inches. 


Square Feet. 


Square Feet. 


U 


.3273 


.0067 


li 


.3926 


.00964 


U 


.4589 


.0133 


2 


.5236 


.0179 


H 


.5890 


.0231 


U 


.6545 


.0284 


21 


.7200 


.0349 


3 


.7853 


.0422 


H 


.8508 


.0494 


34 


.9163 


.0580 


31 


.9817 


.0672 


4 


1.0472 


.0759 


44 


1.1790 


.0976 


5 


1.3680 


.1205 



That part of the shell of a boiler over the fire is the most effective, 
and probably three-eighths of the heat enters the boiler there. If 
the fuel burns with a long flame, passing the whole length of the 
boiler, the whole lower part of the shell will receive heat by radia- 
tion from the flame, but if there is no flame, but only a mass of 
heated gas, then the shell back of the bridge wall is less efficient, 
and only receives heat by the contact of the heated gases. 

Some boiler makers and engineers add the heating surface of 
both heads of the boiler. This gives a somewhat larger commercial 
horse-power ; but as the front head of the boiler receives very little 
heat from the escaping gases, it is safer to omit that head from the 
calculation. If the rear head is included only the actual heating 
surface exposed to the hot gases should be taken, and the area of 
the tube openings should be deducted from the exposed area of the 
head of the boiler. 

To jind the heating surface in a horizontal multitubular boiler. 
Multiply one-half the circumference of the boiler in feet by the 
length of the shell in feet, for the heating surface of the shell. If 
there is an overhang deduct it from the length of the boiler. 

To Jind the area of heating surface of tubes. 
Multiply the circumference of the tubes (either inside or out- 
side, according to which is exposed to heat) in inches by length of 



78 THE SCHOOL HOUSE. 

tube in inches, and reduce the product to square feet by dividing 
by 144. Multiply the square feet in one tube by the number of 
tubes for total heating surface of tubes. 

Add together the square feet of heating surface in the shell of 
the boiler and the square feet of heating surface in the tubes for 
the total heating, surface in the boiler. 

Divide the total heating surface in the boiler by 15 for the boiler 
maker's commercial horse-power of the boiler. 

To find area of tube surface. 
Divide area of grate by 7 or 9, according to whether hard or 
soft coal is used — 7 for soft and 9 for hard coal. 

To f ltd number of tubes. 
Divide collective area of tubes by area of sized tube used. 

To fnd amount -of heating surface. 
Multiply ratio of heating surface to amount of grate surface, by 
the amount of grate surface. 

In designing a boiler, after having found the weight of the 
water to be evaporated per hour or the amount of steam to be 
condensed, it will be necessary to find how many pounds of coal 
this will require to be burned per hour. 

In power boilers it may be assumed that one pound of coal will 
evaporate from y to 10. pounds of water. Dividing the amount of 
water to be evaporated by 9 will give the pounds of coal required 
to be burned per hour. 

Dividing the number of pounds of coal burned per hour by the 
number of pounds of coal burned per hour per foot of grate 
surface, which may be assumed as 12, will give the number of 
square feet of grate surface, and from this the size of the boiler 
can be determined. 

In ordinary low-pressure systems of heating in schoolhouses it is 
not safe to figure as large a number of pounds of coal burned per 
hour, or as small a grate surface. 

When the plant is poorly managed, as it sometimes is by the 
ordinary janitor, it is safer to estimate the amount of water evapo- 
rated by one pound of coal as not exceeding eight pounds, and the 
amount of hard coal burned per hour per foot of grate surface as six 
pounds, or even less. On this basis the grate area would be larger. 

The amount of air space in a grate must be considered. If this 
is too small a stronger draft is required than where it is of 



THE SCHOOL HOUSE. 7!) 

sufficient size to allow the passage of a sufficient quantity of air 
when the fire is packed with ashes or clinkers, as is frequently the 
case near the close of the school clay. 

The material generally used for the shells and heads of steam- 
boilers is the best quality of open-hearth steel, having a tensile 
strength of not less than 55,000 pounds or more than 60,000 pounds 
per square inch, and an elongation of not less than 25 per cent, 
nor more than 30 per cent in a length of 8 inches ; fire-box steel 
being used for shell plates, and flange steel for heads. 

The tubes should be of the best American manufacture and the 
braces and stay-bolts of the best refined iron ; rivets of the best 
quality. As far as practicable the man-hole frames should be of 
pressed steel and the nozzles of cast steel ; the lugs, fronts, bonnets, 
doors and other castings of cast iron adapted to meet the require- 
ments of the particular parts. The edges of shell plates are 
planed, and the riveted joints for the most part are calked by a 
pneumatic calking tool. 

The circumference seams are lapped and single riveted. For 
boilers less than 60 inches in diameter the longitudinal seams are 
lapped and double riveted. Rivet holes are drilled and the 
riveting done with a hydraulic riveter, except necessary hand- 
riveting. 

The drift-pin should be used as little as possible. 

For boilers 60 inches or more in diameter the longitudinal seams 
are secured by the triple-riveted butt joint, the edges of the plate 
being brought together end to end, with a covering plate above and 
below, and riveted through the three sheets. 

Where a boiler is designed for power or high pressure it is much 
better and safer to use the triple-riveted butt joint than to use the 
lap joint. 

In return tubular boilers less than 60 inches in diameter diagonal 
braces are used, one end of each being riveted to the shell and the 
other bolted to a tee-bar, which is riveted to the shell, the tee-bars 
being laid out radially. 

When the diameter is 60 inches or over, through bolts are used, 
running from head to head, with two nuts on each end, one inside 
and one outside the plate. Where the bolts pass through the plate 
the head is stiffened by channel-iron bars, one continuous bar being 
used for each horizontal row of bolts. Sometimes a combination 
of through bolts and diagonal bracing is used. The heads of the 
tubes are beaded over at both ends and secured by a roller expander. 
The holes in the plate for the tubes are drilled, the edges reamed. 



80 THE SCHOOL HOUSE. 

and the corners chamfered off. Where small pipes are attached to 
the outside shell the metal is thickened by reinforcing plates secured 
by rivets. 

For main connections of steam-pipes and safety-valve, nozzles 
are riveted to the shell, the face of the outer flange being turned, 
and the flange drilled to receive the bolts. 

The manhole frames are inside the opening of the shell. The 
manhole plate and yoke are of steel, and the joint packed with a 
lead or rubber gasket. 

Steam domes are not commonly used on Massachusetts school- 
house boilers, as with good construction and proper management 
of the boilers the steam is found to be quite as dry without as with 
them. Mud drums are only used in exceptional cases. 

The boiler maker should furnish with each boiler a cast-iron 
front having ash pit and fire doors protected by linings, grate bars, 
bearers for grates, wall binders, ash-cleaning door and frame, arch 
bars or back plates, cast-iron wall plates and rollers for same, 
anchor bolts and binder bolts; also a pop safety-valve, a steam- 
gauge, a water column with glass gauge and gauge cocks and a 
fusible safety plug ; also a full set of fire tools and rack for the 
same. All boilers should be subjected to a hydrostatic test and 
examined by a boiler inspector. 

In Massachusetts the use of a locked pop safety-valve, set to 
blow off at fifteen pounds, and of a pattern approved by the Chief 
of the District Police, will allow a boiler that is used exclusively 
for heating purposes to be operated without employing a licensed 
engineer or fireman. 

Better service and results will be obtained if a licensed engineer 
or fireman is employed in addition to having the locked pop 
safety-valve. 

An insurance policy in some standard boiler insurance company 
for $400 for one year is generally furnished by the boiler maker. 

Horizontal multitubular return flue boilers are usually made for 
diameters from 24 to 36 inches with r 5 ^-inch shell and 4-inch heads ; 
for 54-inch diameters -|^-inch shell and -|-inch heads. These are 
for 100 pounds working pressure per square inch. 

For 60-inches diameter, boilers generally have |-inch shell and 
4-inch heads, and for 66 to 72-inches diameter T 7 F -inch shell and 
•|-inch heads, for a working pressure of 125 pounds per square 
inch. 

The following table is from the Hodge Boiler Works, East 
Boston, Mass. 



THE SCHOOL HOUSE. 



81 



TABLE 11. 

Standard Sizes of Horizontal Return Tubular Boilers. 

(Externally Fired ) 



Diam. 


Length 


Number 


Outside 


Length 


Area 


Thick- 


Thick- 




Rated 


Approxi- 


Approxi- 
mate Weight! 




of 


of 




of 


Diam- 


of 


through 


ness of 


ness of 


Heating 


Horse- 


mate 


of Castings 


Total 


Shell. 


Shell. 


Tubes. 


eter of 
Tubes 


Tubes. 


Tubes. 


Shell. 


Heads. 


Surface. 


Power. 


Weight of 
Boilers. 


and 
Fixtures. 


Weight. 


In. 


Ft. 


In. 




In. 


Ft. 


Sq. Ft. 


In. 


In. 


Sq. Ft. 


H.P. 


Lbs. 


I.bs. 


Lbs. 


24 


5 


8 


26 


2 


5 


.43 


J. 

4 


3 

8 


80 


5 


1,040 


920 


1,960 


24 


6 


8 


26 


2 


6 


.43 


4 


8 


95 


6 


1.165 


920 


2,085 


24 


7 


8 


26 


2 


7 


.43 


1 
4 


3. 

8 


110 


7 


1,290 


920 


2,210 


24 


8 


8 


26 


2 


8 


.43 


1 
4 


a 

8 


125 


8 


1 ,450 


920 


2,370 


24 


9 


8 


26 


2 


9 


.43 


JL 
4 


3 

8 


140 


9 


1,575 


920 


2,495 


30 


6 


9 


36 


2 


6 


.60 


JL. 
4 


3 

8 


129 


9 


1,550 


1,400 


2,950 


30 


7 


9 


36 


2 


7 


.60 


JL 
4 


3 

8 


150 


10 


1,750 


1,475 


3,225 


30 


8 


9 


36 


2 


8 


.60 


X 
4 


a 

8 


170 


11 


1,950 


1.475 


3,425 


30 


9 


9 


30 


2 


9 


.60 


JL 
4 


1 

8 


191 


13 


2,100 


1,475 


3,575 


30 


10 


9 


36 


2 


10 


.6'i 


X 
4 


3 

8 


211 


14 


2,250 


1.530 


3.780 


30 


11 


!i 


36 


2 


11 


.60 


X 
4 


8 


232 


15 


2.400 


1,630 


4,030 


30 


12 


9 


36 


2 


12 


.60 


X 
4 


a 

8 


252 


17 


2,600 


1,800 


4,400 


36 


8 


3 


34 


24 


7 


.94 


X 

4 


3 

8 


183 


12 


2.160 


2,025 


4,185 


. 36 


9 


3 


34 


24 


8 


.94 


X 
4 


a 

8 


208 


14 


2,400 


2,025 


4,425 


36 


10 


:s 


34 


24 


9 


.94 


X 

4 


a 

8 


233 


16 


2.550 


2.100 


4,650 


36 


11 


3 


28 


3 


10 


1.15 


X 
4 


a 

8 


222 


15 


2,750 


2,250 


5,000 


36 


12 


3 


28 


3 


11 


1.15 


X 
4 


3 
8 


2 J, 3 


16 


2,900 


2,250 


5,150 


36 


13 


3 


28 


3 


12 


1.15 


X 
4 


a 

8 


264 


18 


3,200 


2,450 


5,650 


42 


10 


3 


38 


3 


9 


1 .57 


1 6 


a 

8 


309 


21 


3,600 


2,500 


6.100 


42 


11 


:'. 


38 


3 


10 


1.57 


1 fi 


a 

8 


341 


23 


4,050 


2,500 


6.550 


42 


12 


3 


38 


3 


11 


1.57 


_5._ 
1 6 


a 

8 


374 


25 


4,260 


2,725 


6,985 


42 


13 


3 


38 


3 


12 


1.57 


1 « 


:; 


407 


27 


4.525 


2,725 


7,250 


42 


14 


3 


38 


3 


13 


1.57 




a 

8 


440 


29 


4,850 


2,725 


7,575 


42 


15 


3 


38 


3 


14 


1.57 


_5- 
1 6 


I 


473 


32 


5,200 


2,725 


7,925 


42 


16 


3 


38 


3 


15 


1.57 


_5- 
1 6 


a 

8 


506 


34 


5,450 


3,000 


8,450 


48 


11 


3 


49 


3 


10 


2.02 


.5- 

i a 


a 

8 


432 


29 


5,150 


3,250 


8.400 


48 


12 


;'. 


49 


3 


11 


2 02 


1 6 


a 

8 


474 


32 


5 55(1 


3,360 


8.910 


48 


13 


:; 


49 


3 


12 


2.02 


.5. 

1 fi 


a 

8 


515 


34 


6.000 


3,360 


9,360 


48 


14 


3 


49 


3 


13 


2.02 


_5_ 

i a 


a 

8 


557 


37 


6,300 


3.360 


9,660 


48 


15 


3 


49 


3 


14 


2. "2 


1 6" 


| 


599 


40 


6,600 


3,750 


10,350 


48 


15 


3 


41 


34 


14 


2.36 


.5. 

1 6 


a 

8 


593 


40 


6,750 


3,750 


10.500 


48 


16 


3 


49 


3 


15 


2.02 


_5_ 

i a 


a 


640 


43 


7,000 


3,900 


10,900 


48 


16 


:•> 


41 


34 


15 


2.36 


I 6 


3 

8 


633 


42 


7.150 


3,900 


11.1150 


48 


re 


3 


30 


4 


15 


2.3 


1 


a 

8 


552 


37 


7,000 


3,900 


10.900 


48 


17 


3 


49 


3 


16 


2.02 


1 6 


3 

8 


682 


45 


7.400 


3.900 


11,300 


48 


17 


3 


41 


34 


16 


2.36 


1 il 


a 

8 


c.Cs 


45 


7,500 


3,900 


11.400 


48 


17 


3 


30 


4 


16 


2.3 




:; 

s 


590 


39 


7,400 


3,900 


11,300 


54 


15 


3 


60 


3 


14 


2 47 


XJL 
3 2 


3 

s 


725 


48 


7800 


4.200 


12,000 


54 


15 


3 


49 


34 


14 


2.82 


XX 
3 2 


a 

8 


703 


47 


7,900 


4,200 


12.100 


54 


15 


3 


42 


4 


14 


3.22 


1 L 
3 2 


a 

s 


696 


46 


8.250 


4,V00 


12,450 


54 


16 


3 


60 


3 


15 


2.47 


XL 
3 2 


3 

8 


116 


52 


8,200 


4,400 


12.600 


54 


16 


3 


49 


34 


15 


2.82 


XX 
3 2 


s 

8 


752 


50 


8,300 


4,400 


12,700 


54 


16 


3 


42 


4 


15 


3 22 


XL 
3 2 


-3 
8 


745 


50 


8,700 


4,400 


13,100 


54 


17 


3 


60 


3 


16 


2.47 


11 
32 


i 
8 


826 


55 


8,650 


4,400 


13,050 







82 




THE 


SCHOOL 


HOUSE. 




















TABLE 11 


. — Continued 










Diam. 


Length 


Number 


Outside 


Length 


Area 


Thick- 


Thick- 




Rated 


Approxi- 


Approxi- 
mate Weight 




of 


of 


of 


Diam- 


of 


through 


ness of 


ness of 


Heating 


Horse- 


mate 


of Castings 


Total 


Shell. 


Shell. 


Tubes. 


eter of 


Tubes. 


Tubes. 


Shell. 


Heads. 


Surface. 


Power. 


Weight of 


and 


Weight 










Tubes. 














Boilers. 


Fixtures. 




In. 


Ft. 


In. 




In. 


Ft. 


Sq. Ft. 


In. 


In. 


Sq. Ft. 


H.P. 


Lbs. 


Lbs. 


Lbs. 


54 


17 


3 


49 


34 


16 


2.82 


11 
32 


2. 

8 


801 


53 


8,900 


4,400 


13,200 


54 


17 


3 


42 


4 


16 


3.22 


11 
32 


.3 

8 


793 


53 


9,150 


4,400 


13,550 


54 


18 


3' 


60 


3 


17 


2.47 


22 


8 


876 


58 


9,100 


4,400 


13,500 


54 


18 


3 


49 


H 


17 


2.82 


11 
32 


2 

8 


850 


57 


9,200 


4,400 


13,600 


54 


18 


3 


42 


4 


17 


3.22 


11 
32 


2 

a 


841 


56 


9,600 


4,400 


14,000 


60 


15 


3 


80 


3 


14 


3.3 


8 


1 

2 


942 


63 


10,450 


5,150 


15,500 


60 


15 


3 


64 


U 


14 


3 69 


3 

8 


1 
2 


898 


60 


10,650 


5,150 


15,800 


60 


15 


3 


58 


4 


14 


4.45 


3 

8 


1 
2 


931 


62 


11,350 


5,150 


16,500 


60 


16 


3 


80 


3 


15 


3.3 


3. 

8 


1 
2 


1,008 


67 


11.050 


5,150 


16,200 


60 


16 


3 


64 


34 


15 


3.69 


2 

8 


1 
2 


960 


64 


11,250 


5,150 


16,400 


60 


16 


3 


58 


4 


15 


4.45 


3. 

8 


1 
2 


996 


66 


11,950 


5,150 


17,100 


60 


17 


3 


80 


3 


16 


3 3 


2 
8 


1 
2 


1,073 


72 


11,800 


5,150 


16,950 


60 


17 


3 


64 


34 


16 


3.69 


2 
8 


- 1 
2 


1,022 


68 


12,000 


5,150 


17,150 


60 


17 


3 


58 


4 


16 


4.45 


2 

8 


JL 
2 


1,061 


71 


12,700 


5,150 


17,850 


60 


18 


3 


80 


3 


17 


3.3 


2 

8 


1 
2 


1,139 


76 


12,560 


5,150 


17,710 


60 


18 


3 


64 


u 


17 


3 69 


2. 
8 


1 
2 


1,085 


72 


12,780 


5,150 


17,930 


60 


18 


3 


58 


4 


17 


4.45 


2. 

8 


1 
2 


1,125 


75 


13,450 


5,150 


18,600 


66 


16 


4 


110 


3 


15 


4 54 


16 


1 
2 


1,348 


90 


14,600 


5,400 


20,000 


66 


16 


4 


79 


34 


15 


4.55 


-Z- 
1 6 


1 
2 


1,168 


78 


14,600 


5,400 


20,000 


66 


16 


4 


62 


4 


15 


4.76 


_3_ 
16 


1 
2 


1,073 


72 


14,600 


5,400 


20,000 


66 


17 


4 


110 


3 


16 


4 54 


-T- 
16 


1 
2 


1,436 


96 


15.500 


5,400 


20,900 


66 


17 


4 


79 


H 


16 


4.55 


.1. 
16 


1 
2 


1,244 


83 ' 


15,400 


5,400 


20,800 


66 


17 


4 


62 


4 


16 


4.76 


.1. 
] 6 


1 
2 


1,142 


76 


15 500 


5,400 


20.900 


66 


18 


4 


110 


3 


17 


4.54 


.1. 
1 6 


1 
2 


1,524 


102 


16,300 


5,400 


21,700 


66 


18 


4 


79 


34 


17 


4.55 


tV 


i 


1,320 


88 


16,200 


5,400 


20,600 


66 


18 


4 


62 


4 


17 


4.76 


16 


i 

2 


1,212 


81 


16,300 


5,400 


21,700 


72 


16 


4, 


140 


3 


15 


5.77 


) 6 


1 
2 


1.689 


113 


16,100 


5,650 


21,750 


72 


16 


4 


92 


34 


15 


5 3 


_1_ 
1 6 


1 
2 


1,352 


90 


16,375 


5,650 


22,025 


72 


16 


4 


76 


4 


15 


5 83 


JL- 
1 6 


1 
2 


1,296 


86 


16,270 


5,650 


21,920 


72 


17 


4 


140 


3 


16 


5 77 


1 6 


1 
2 


1,799 


120 


16,725 


5,650 


22,375 


72 


17 


4 


92 


34 


16 


5.3 


JL- 
1 6 


1 
2 


1,440 


96 


17,000 


5,650 


22.650 


72 


17 


4 


76 


4 


16 


5.83 


-1. 
1 6 


1 
2 


1 380 


92 


16,895 


5,650 


22,545 


72 


18 


4 


140 


3 


17 


5.77 


.1. 
1 6 


1 
2 


1,909 


128 


17,450 


5,650 


23,100 


72 


18 


4 


92 


34 


17 


53 


JL. 
1 6 


2 


1,528 


102 


17,725 


5,650 


23,375 


72 


18 


4 


76 


4 


17 


5 83 


_2_ 
l 6 


1 
2 


1,464 


98 


17,620 


5,650 


23,270 


72 


19 


4 


92 


34 


18 


5 3 


.2. 
1 6 


1 
2 


1,615 


10S 


18,750 


5,650 


24,400 


72 


20 


4 


92 


34 


19 


5.3 


.1. 
16 


1 
2 


1,703 


103 


19,680' 


5,650 


25,330 


72 


21 


4 


92 


34 


20 


5.3 


-1_ 
1 6 


1 
2 


1,790 


119 


20,580 


5,650 


26,234 



These horizontal return tubular boilers have the same dimen- 
sions, whether they are set with overhanging fronts or flush fronts, 
and the table may be used indiscriminately for either. 

The heating surface given in the table is the area which is 
directly exposed to the heat of the products of combustion; that is, 



THE SCHOOL HOUSE. 83 

the exterior surface, in the case of the shell and heads, and the 
interior surface in the case of the tubes. 

The rated horse-power given is based upon 15 square feet of 
heating surface per horse-power. 

With the draft of a good chimney 80 feet high and proper flue 
connections, the rated capacity can easily be produced under work- 
ing conditions with good coal, it being understood that a horse- 
power refers to the evaporation of 344 pounds of water per hour 
from and at 212° F. (A.S.M.E. standard). 

Beyond the rating stated there is a surplus capacity of at least 
one-third when the full draft of the chimney is on and the fire is 
urged. 

With high chimneys and the best grade of bituminous coal the 
boilers can be worked to much higher capacities than those noted 
in the table. 

The thickness of boiler plates within ordinary use makes but 
little difference in the ability of the plate to conduct heat. 

A coating or incrustation on the plates and tubes makes consid- 
erable difference in the efficiency and life of a boiler and should be 
carefully guarded against. This is a matter that is often badly 
neglected by janitors in school buildings. 

The setting of a boiler is a matter to be carefully attended to in 
order that cracks may not appear and allow air to enter and cool 
the temperature of the fire and gases in the furnace. 

In setting a boiler on marshy or filled ground especial care 
should be taken to secure a good foundation, and in some cases a 
thick foundation of good concrete should be put under the whole 
apparatus to prevent unequal settling and cracking of the walls. 

Before a boiler is set the nature of the ground should be carefully 
investigated. 

In setting the fire-brick in a furnace they should be laid with but 
a small quantity of fire-clay between them, but sufficient to level 
the work. 



84: 



THE SCHOOL HOUSE. 



TABLE 12. 
{Hodge Boiler Works, East Boston, A/ass.) 

DIMENSIONS RELATING TO BRICK SETTING FOR HORIZON- 
TAL RETURN TUBULAR BOILERS; NUMBER OF BRICKS 
GIVEN BEING APPROXIMATE. 





Ft. In. 


Ft. In. 


Ft. In. 


Ft. In. 


Ft. In. 


Ft. In. 


Diameter of shell 


42 


48 


54 


60 


66 


72 


Length of shell over all 


13 3 


15 3 


16 3 


16 3 


17 4 


17 4 


Length of brick setting 














over all with overhang- 














ing fronts 


15 3 


17 6 


18 6 


18 6 


19 7 


19 7 


Length of brick setting 














over all with flush fronts 


16 6 


18 9 


19 9 


19 9 


20 10 


20 10 


Width of brick setting for 














single boiler 


7 7 


8 1 


8 7 


9 1 


9 7 


10 1 


Increase in width of set- 














ting for each additional 














boiler in a battery 


5 11 


6 5 


6 11 


7 5 


7 11 


8 5 


Length of grate 


3 6 


4 


4 6 


5 


5 6 


6 


Width of grate 


3 6 


4' 


4 6 


5 


5 6 


6 


Vertical distance from 














floor to shell 


3 9 


3 9 


4 


4 


4 


4 


Vertical distance from 












, 


grate to shell at front 














end 


22 


22 


24 


24 


24 


24 


Vertical distance from 














floor to top of brick 














work 


7 7 


8 1 


8 10 


9 4 


9 10 


10 4 


Number of red brick re- 














quired for setting single 














boiler overhanging 














front 


11,923 


14,563 


16,819 


17,977 


20,048 


21,359 


Flush front 


12,860 


15,568 


17,903 


19,110 


21,245 


22,624 


Number of fire brick re- 














quired for a single boiler 


765 


884 


1,059 


1,179 


1,359 


1,526 


Number of red brick re- 














quired for each addi- 














tional boiler of a battery 














overhanging front 


7,757 


9,550 


11,022 


12,065 


13,361 


14,323 


Flush front 


8,335 


10,174 


11,695 


12,773 


14,109 


15,116 


Number of fire brick for 














each additional boiler 














of a battery 


765 


884 


1,059 


1,179 


1,359 


1,526 


Number of red brick re- 














quired for each addi- 














tional length of one foot 














in the length of a single 














boiler 


703 


754 


813 


850 


898 


949 


Number of red brick re- 














quired for each addi- 














tional length of one foot 














in the length of each 














additional boiler 


434 


46S 


505 


531 


561 


595 



NOTE. — When the thickness of the inside walls is 8 inches, instead of 12 inches, to which the 
above table applies, the number of red brick required for the various sizes of boilers given is as 
follows: 



THE SCHOOL HOUSE. 
TABLE 13. 



Single boiler, overhang- ) 
ing front. J 

Single boiler, flush front 

Each additional boiler, \ 
overhanging front J 

Each additional boiler, 
flush front 



10,14G 


12,534 


14,429 


15,327 


17,392 


10,962 


13,412 


15,383 


16,331 


18,458 


5,751 


7,189 


8,315 


8,879 


10,238 


6,281 


7,75'J 


8,925 


9,529 


10,928 



18,585 
W,713 
11,084 
11,814 



Smoke Flies for Steam-Boilers. 

The smoke flues connecting steam-boilers to the chimney should 
be constructed of iron; brick ones do not prove satisfactory. 

In most smoke-flue work No. 12 tank iron is used unless other- 
wise specified. 

The two kinds generally used are those of circular cross-section 
and those of a rectangular shape. 

The seams of circular flues are lap riveted, and the rectangular 
ones are joined together at the corners by angle irons, and where 
the flue is of considerable width it is stiffened by the same means. 
The short branch flue which connects immediately to the boiler 
(the uptake in a horizontal boiler) is provided with a clamper. 
The main flue between the last boiler and the chimney is fitted 
with a regulating damper for controlling the entire battery of 
boilers. The size of the flue should be equal to the collective area 
of the tube openings in all the boilers to which it is connected. A 
clean-out which can be closed air-tight should be provided. 

Flues should be as short and straight as practicable, and where 
a change of direction is made it should be by a curve rather than a 
sharp or square angle. 

Rules for Determining Pressure a Boiler will Sustain : 
United States Governme?tt Standard. 
Divide tensile strength of metal by 6 and multiply by thickness 
of stock. Divide product by radius of boiler in inches. The 
quotient is the steam pressure the boiler will sustain. 

Massachusetts hispcctors' Rule. 
Multiply the thickness of sheet by tensile strength. Multiply 
this product by 56 per cent if single riveted, or by 70 per cent if 
double riveted; by 80 or 85 per cent if butt-strap riveted. The 
quotient is the bursting pressure. For safe pressure divide burst- 
ing pressure by 4£ or 5, according to the condition of the boiler. 



86 THE SCHOOL HOUSE. 

Water-tub^ Boilers. 

Water-tube boilers are boilers in which the water is inside the 
tubes and the heat is applied from the outside, instead of having 
the water on the outside and the heat inside the tubes, as in hori- 
zontal or upright boilers. 

This class of boilers is used to a limited extent in scboolhouses 
in Massachusetts ; generally where a mechanical (fan) system of 
heating and ventilation has been installed, or where the architect 
has not provided a boiler-room of sufficient size. 

They generate steam quickly and can be forced when under the 
charge of a skilful engineer, and have given good results, especially 
where a fan is used ; but for ordinary small or moderate size school- 
houses the return tubular class is to be preferred. 

Upright Tubular Boilers. 

Upright tubular boilers have been used in schoolhouses ; but to 
a limited extent and where it has been desired to run an engine at 
high pressure to drive a fan or blower. 

They occupy but little floor space, but in the ordinary school- 
house basement require that a pit be provided to keep the top of 
the boiler sufficiently below the ceiling. 

It is generally better to use a low-pressure engine having a 
cylinder of large diameter and short stroke, rather than to install a 
high-pressure engine driven by steam at high pressure from an 
upright boiler. 

Cast-Iron Sectional Boilers. 

Cast-iron sectional boilers have been used to a considerable extent 
in schoolhouses, but the results obtained are not in the majority of 
cases as satisfactory as when the return horizontal tubular class 
are used. 

, There are many different patterns : good, indifferent and bad. 
Different manufacturers claim their design to be the best, and to 
describe them all would be beyond the scope of this book. 

In many cases a higher rating for efficiency is given in catalogues 
than is shown in the actual work performed. If the designer of 
the heating system in a schoolhouse depends upon the catalogue 
rating of many of this class of boilers, he will be sadly disappointed 
in the final test. 

A large factor of safety should be allowed for rating many of 
this class of boilers. In installing them in schoolhouses it is well 
to obtain from the manufacturer a good and sufficient guarantee 
that the boiler will do the work required. 



THE SCHOOL HOUSE. 87 

Manv of this class have a large amount of heating surface and 
a small amount of water and steam space, and when forced the 
water is carried into the heating coils or radiators and trouble is 
caused by low water in the boiler, melting out the fusible plug and 
cracking sections of the boiler. 

The writer has seen many cases where this has occurred and 
caused the shutting down of the heating apparatus. This has 
been particularly noticeable in the small cast-iron sectional boilers 
so generally used for heating the vent shafts and for supplying 
direct radiation in corridors, teachers' rooms, etc., in school - 
houses. 

Where this class of boilers is used care should be taken to select 
a boiler of ample size to do the work required, and one that has 
a proper proportion of heating surface to the water and steam 
space; also one that does not have a large, flat, unstayed heating 
surface. 

REQUIREMENTS OF BOILER INSPECTION DEPARTMENT OF 
MASSACHUSETTS DISTRICT POLICE AS TO FITTINGS FOR 
LOW-PRESSURE HEATING BOILERS. 

Upon all steam boilers used for heating purposes, having a grate area of 
over two square feet, and subject to inspection by this department, the fol- 
lowing fittings must be provided, being deemed necessary for safety. 

One safety-valve on each boiler with no obstruction between valve and 
boiler. If pressure carried is to be below 25 pounds, the least area of the 
safety-valve in inches is to be reckoned by dividing the area of grate in 
square feet by 2£ if a pop valve is used, or by two if a lever, dead- weight, or 
simple spring valve is used. 

One steam gauge on each boiler, connected with syphon or equivalent 
device between gauge and boiler, to fill gauge spring with water. The supply 
pipe is to come from steam space of boiler. 

Each boiler must have at least two try-clocks, the lower one to be placed 
24 inches above fusible plug or lowest safe water line. Where a glass is also 
used the lower end of glass must be above the fusible plug or lowest safe 
water line. 

Each boiler must be provided with stop valve on main steam pipe leading 
from boiler. Each boiler must have check valve and stop valve on main 
return pipe. 

Where a damper regulator is used, the pressure supply pipe must be taken 
from the steam space of the boiler, with proper water syphon. 

SAFETY-VALVES FOR HIGH PRESSURE. 

If pressure carried is between 25 and 100 pounds, the area of safety-valve 
in inches shall equal the area of grate in square feet divided by 3, for lever cr 
dead-weight valves, and by 'Ah for pop valves If pressure is above 100 pounds, 
divide by 5 for pop valves and by 4 for lever or dead-weight valves. 



88 THE SCHOOL HOUSE. 

SECTIONS 78 TO 86 INCLUSIVE OF CHAPTER' 102 OF THE 
REVISED LAWS OF MASSACHUSETTS, RELATIVE TO THE 
LICENSING OF ENGINEERS AND FIREMEN. 

As Amended by Chapter 310, Acts of 1905. 

Section 78. No person shall have charge of or operate a steam boiler or 
engine in this Commonwealth, except boilers and engines upon locomotives, 
motor road vehicles, boilers in private residences, boilers in apartment 
houses of less than five flats, boilers under the jurisdiction of the United 
States, boilers used for agricultural purposes exclusively, boilers of less than 
eight horse power, and boilers used for heating purposes exclusively which 
are provided with a device approved by the chief of the district police 
limiting the pressure carried to fifteen pounds to the square inch, unless he 
holds a license as hereinafter provided. The owner or user of a steam 
boiler or engine, other than boilers or engines above excepted, shall not 
operate or cause to be operated a steam boiler or engine for a period of more 
than one week, unless the person in charge of and operating it is duly 
licensed. 

Section 79. If such steam engine or boiler is found to be in charge of 
or operated by a person who is not a duly licensed engineer or fireman and, 
after a lapse of one week from such time, it is again found to be operated by 
a person who is not duly licensed, it shall be deemed prima facie evidence 
of a violation of the provisions of the preceding section. 

Section 80. The words "have charge" or "in charge," in the two 
preceding sections, shall designate the person under whose supervision a 
boiler or engine is operated. The person operating shall be understood to 
mean any and all persons who are actually engaged in generating steam in a 
power boiler. 

Section 81. Whoever desires to act as engineer or fireman shall apply 
for a license therefor to the examiner of engineers for the city or town in 
which he resides or is employed, upon blanks to be furnished by the 
examiner. The application shall be accompanied by a fee of one dollar and 
shall show his total experience. Wilful falsification in the matter of state- 
ments contained in the application shall be deemed sufficient cause for the 
revocation of said license at any time. The applicant shall be given a 
practical examination and, if found competent and trustworthy, he shall 
receive, within six days after the examination, a license graded according to 
the merits of his examination, irrespective of the grade of license for which 
he applies. The applicant shall have the privilege of having one person 
present during his examination, who shall take no part in the same, but who 
may take notes if he so desires. No person shall be entitled to receive more 
than one examination within ninety days, except in the case of an appeal as 
hereinafter provided. A license shall continue in force for three years, or 
until it is revoked for the incompetence or untrustworthiness of the- licensee ; 
and a license shall remain revoked until a new license is granted. A license, 
unless revoked, shall be renewed by an examiner of engineers upon 
application and without examination, if the application for renewal is made 
within six months after its expiration. If a new license of a different grade 
is issued, the old license shall be destroyed in the presence of the examiner. 
If a license is lost by fire or other means,, a new license shall be issued in its 



THE SCHOOL HOUSE. 89 

place, without re-examination of the licensee, upon satisfactory proof of such 
loss to an examiner. 

Section 82. Licenses shall be granted according to the competence of 
the applicant, and shall be distributed in the following classes : Engineers' 
licenses: — First class, to have charge of and operate any steam plant. 
Second class, to have charge of and operate a boiler or boilers, and to have 
charge of and operate engines, no one of which shall exceed one hundred 
and fifty horse power, or to operate a first-class plant under the engineer in 
direct charge of the plant. Third class, to have charge of and operate a 
boiler or boilers not exceeding in the aggregate one hundred and fifty horse- 
power, and an engine not exceeding fifty horse-power, or to operate a 
second-class plant under the engineer in direct charge of the plant Fourth 
class, to have charge of and operate hoisting and portable engines and 
boilers. Firemen's licenses: — Extra first class, to have charge of and 
operate any boiler or boilers. First class, to operate any boiler or boilers. 
Second class, to have charge of and operate any boiler or boilers where the 
pressure carried does not exceed twenty-five pounds to the square inch, or 
to operate high pressure boilers under the engineer or fireman in direct 
charge thereof. A person holding an extra-first or first-class fireman's 
license may operate a third-class plant under the engineer in direct charge of 
the plant A person who desires to have charge of or to operate a particular 
steam plant or type of plant may, if he files with his application a written 
request signed by the owner or user of said plant for such examination, be 
examined as to his competence for such service and no other, and if found 
competent and trustworthy shall be granted a license for such service and 
no other. 

Section 83. The horse-power of a boiler shall be ascertained upon the 
basis of three horse-power for each square foot of grate surface, for a power 
boiler, and on the basis of one and one-half horse-power for each square foot 
of grate surface, if the boiler is used for heating purposes exclusively. The 
engine power shall be reckoned upon a basis of a mean effective pressure of 
forty pounds per square inch of piston for a simple engine; fifty pounds for 
a condensing engine; and seventy pounds for a compound engine, reckoned 
upon area of high-pressure piston. 

Section 84. A person who is aggrieved with the action of an examiner 
in refusing or revoking a license may, within one month .after his decision, 
appeal therefrom to the remaining examiners, who shall together act as a 
board of appeal, and a majority of whom shall have the power to hear the 
parties and pass upon the subjects of appeal. The applicant may have the 
privilege of having one first-class engineer present during the hearing of his 
appeal, but he shall take no part therein. The decision of the majority of 
such remaining examiners so acting shall be final if approved by the chief of 
the district police 

Section 85. An engineer's or fireman's license, granted under the 
provisions of the seven preceding sections or the corresponding provisions 
of earlier laws, shall be placed so as to be easily read in a conspicuous place 
in the engine room or boiler room of the plant operated by the holder of 
such license. 

Section 86. The boiler inspection department of the district police shall 
act as examiners and enforce the provisions of the eight preceding sections 



90 THE SCHOOL HOUSE. 

and whoever violates any of the provisions of said sections shall be 
punished by a fine of not less than ten nor more than three hundred dollars 
or by imprisonment for not more than three months. A trial justice shall 
have jurisdiction of complaints for violations of the provisions of the eight 
preceding sections, and in such cases, may impose a fine of not more than 
fifty dollars. All members of the boiler inspection department of the 
district police shall have authority in the pursuance of their duty to enter 
any premises on which a boiler or engine is situated, and any person who 
hinders or prevents or attempts to prevent any state boiler inspector from so 
entering shall be liable to the penalty as specified in this section. 

[Chap. 310, Acts of 1905.] 
********* 

Section 4. All acts and parts of acts inconsistent herewith are hereby 
repealed : provided, however, that this act shall not apply to the exemptions 
specified in section seventy-eight of chapter one hundred and two of the 
Revised Laws or that such repeal shall not invalidate any license granted 
under the acts repealed; and licensees holding licenses so granted shall have 
the powers given to licensees of the same class by section two of this act. 

Section 5. This act shall take effect on the first day of July in the year 
nineteen hundred and five. {Approved April 20, 1903. ] 

[Amendment of 1905.] 
[Chap. 472, Acts of 1905.] 
An Act relative to the inspection of steam boilers. 
Be it enacted, etc., as follows : 

Section 1. All steam boilers of more than three horse power, except 
boilers upon locomotives, in private residences, or under the jurisdiction of 
the United States, or boilers used exclusively for agricultural, horticultural 
or creamery purposes, shall be inspected either by the district police or by 
an insurance company authorized to insure boilers within the Common- 
wealth. Such inspection shall be made internally and externally at least 
once in each year. The owner or user of any steam boiler inspected by the 
district police shall pay to the inspector the sum of five dollars at each 
internal, and two dollars for each external, inspection for every boiler 
so inspected. 

Section 2. Every insurance company shall forward to the chief of the 
district police within fourteen days after each internal and external 
inspection a report of every boiler so inspected by it. Such reports shall be 
made on blanks furnished by the chief of the district police, and shall 
contain any recommendations that the insurance company may think it 
desirable to make. Notice shall be given by the insurance company or the 
inspector to the owner or user of the boiler inspected of the pressure at 
which the boiler may safely be operated. 

Section 3. Any insurance company failing to make a report as above 
provided shall be fined not more than five hundred dollars for every such 
failure. Any owner failing to comply with the requirements of the insur- 
ance company inspecting his boiler, after notice by the chief of the district 
police, shall be liable to a fine of not more than five hundred dollars for 
such failure, and the use of said boiler may be enjoined in the manner 



THE SCHOOL HOUSE. 91 

provided in section four of chapter one hundred and five of the Revised 
Laws. The district police shall have authority in the discharge of their 
duty to enter upon any premises where steam boilers are located, for the 
purpose of enforcing the provisions of this act 

Section 4. All acts and parts of acts inconsistent herewith are hereby 
repealed. [Approved May 26, /goj.] 

REVISED LAWS OF MASSACHUSETTS. 

Chapter 105. 

Of the Inspection of Steam Boilers. 

Section 1. The chief of the district police shall detail ten members of 
the inspection department of the district police, who, under his direction, 
shall inspect stationary steam boilers and their appurtenances, shall act as 
examiners of engineers and firemen and shall report to said chief. 

Section 2. Whoever owns or uses or causes to be used a steam boiler, 
except boilers upon locomotives, in private residences, under the jurisdiction 
of the United States or under the periodically guaranteed inspection of com- 
panies which have complied with the laws of this Commonwealth, boilers 
used exclusively for agricultural, horticultural and creamery purposes or 
boilers of less than three horse power, shall annually report to the chief of 
the district police the location of such steam boiler. 

Section 3. Each boiler designated in the preceding section and not therein 
excepted shall be inspected by the inspector of boilers for the district in which 
said boiler is located, and if he so orders the owner or user shall have the 
boiler blown off dry and the man-hole and hand-hole covers thereon removed, 
ready for inspection, upon the day designated by the inspector, who shall 
give the owner or user of said boiler fourteen days notice in writing of the 
day upon which he will make such internal inspection, which shall not be 
required oftener than twice a year 

Section 4. If, upon examination, said inspector finds the boiler to be 
worthy and in safe working order, with the fittings necessary to safety, and 
properly set up, he shall grant to the owner or user thereof a certificate of 
inspection, and thereupon said owner or user may use the boiler mentioned 
in the certificate. If the inspector finds that the boiler is not in safe con- 
dition, or is not provided with fittings necessary to safety or with fittings not 
properly arranged, he shall withhold his certificate until the boiler and fittings 
are put into condition satisfactory to him ; and the owner or user shall not 
operate such steam boiler or cause it to be operated until such certificate has 
been granted. The owner or user of such boiler shall pay to the inspector 
at each inspection two dollars for each boiler inspected. The supreme judi- 
cial court or the superior court, upon the application of the inspector of 
boilers approved by the chief of the district police, shall have jurisdiction in 
equity to restrain the owner or user of such boiler from operating it without 
certificate. 

Section 5. If the inspector finds that the owner or user of a steam 
boiler is putting too much pressure upon it, he may fix the maximum pres- 
sure to be carried by it and shall prescribe a device to prevent it from carry- 
ing more than the maximum pressure designated, which shall be approved 
by the chief of the district police and which the owner or user shall place or 
cause to be placed upon said boiler. No person shall in any manner tamper 



92 THE SCHOOL HOUSE. 

with such device, or load the safety-valve to a greater pressure than that 
allowed by the inspector. 

Section 6. Whoever violates the provisions of the preceding sections of 
this chapter shall be punished by a fine of not more than five hundred dollars 
or by imprisonment for not more than six months, or by both such fine and 
imprisonment. 

Section 7. The mayor and aldermen of any city except Boston, or the 
selectmen of a town, or any person by them authorized, may, after notice to 
the parties interested, examine any steam engine or steam boiler therein, 
whether fixed or portable ; and for that purpose may enter any house, shop 
or building ; and if upon such examination it appears probable that the use 
of such engine or boiler is unsafe, they may issue a temporary order to 
suspend such use ; and if, after giving the parties interested, so far as known ; 
an opportunity to be heard, they adjudge such engine or boiler to be unsafe 
or defective or unfit to be used, they may pass a permanent order prohibiting 
the use thereof until it is tendered safe. If, after notice to the owner or 
person having charge thereof, such engine or boiler is used contrary to either 
of such orders, it shall be deemed a common nuisance, without any other 
proof thereof than its use. 

Section 8. The mayor and aldermen and selectmen may abate and 
remove a steam engine or steam boiler which has been erected or used con- 
trary to the provisions of the preceding section in the same manner as boards 
of health may remove nuisances under the provisions of sections sixty-seven, 
sixty-eight and sixty-nine of chapter seventy-five. 

Section 9. No person shall manufacture, set up or use a steam boiler 
or cause it to be used unless it is provided with a fusible safety plug, made of 
lead or some other equally fusible material and of a diameter of not less than 
one-half an inch, placed in the roof of the fire box, if a fire box is used, and 
in all cases, in a part of the boiler fully exposed to the action of the fire, and 
as near the top of the water line as any part of the fire surface of the boiler. 

Section 10. Whoever, without just and proper cause, removes the safety 
plug from a boiler or substitutes therefor any material more capable of 
resisting the action of the fire than the plug so removed shall be punished 
by a fine of not more than one thousand dollars. 

Section 1 1 . Whoever manufactures, sets up or knowingly uses or causes 
to be used for six consecutive days a steam boiler, unprovided with a safety 
fusible plug as described in section nine, shall be punished by a fine of not 
more than one thousand dollars. 

Section 12. The provisions of the five preceding sections shall not 
apply to a boiler for which a certificate of inspection issued under the provi- 
sions of sections four and five is in force 



CHAPTER VI. 



STEAM-PIPES 



THE success of a steam-heating apparatus will to a consid- 
erable extent depend upon the proper size, location, 
grading, dripping and valving of the steam-pipes. 
In the earlier installment of gravity syste'ms of steam-heating in 
schoolhouses trouble was often caused by the use of too small pipes, 
both for supply and return. At the present time larger pipes are 
used and much better results are obtained. 

In piping indirect radiators the following may be considered a 
safe rule for size of supply and return pipes when a gravity system 
is used and steam supplied at low pressure, five pounds or less. 

TABLE 14. 



Square Feet of Indirect Radiators. 


Supply. In Inches. 


Return. In Inches. 


30 or less 

30 to 50 

50 to H)0 

100 to 160 


1 

H 
U 
2 


1 

1 

H 
H 



It is not advisable to make indirect radiator stacks with more 
than 160 square feet of radiating surface, and 140 is to be preferred 
to 160 if good circulation is expected. Three-quarter-inch pipe is 
the smallest that should be used for return, even from very small 
radiators. For indirect steam-heating the supplv pipes should have 
double the area in cross section of those supplying direct radiators. 

For direct radiation steam mains and risers the rule adopted by 
many heating contractors is T 1 -^ the square root of the heating sur- 
face in square feet for the diameter of the supply pipes in inches ; 
or, square the diameter of the pipe in inches for the number of 
hundred feet of direct radiation it will supply. 

By using pipe one size larger than that called for by these rules 
better results will be obtained. Another rule is to divide the amount 
of direct heating surface in square feet by 100, divide the quotient 
by .7854, then extract the square root of the quotient ; the result 
will be the diameter of the pipe in inches. 



94 THE SCHOOL HOUSE. 

As a general rule, return pipes should be one size smaller than 
the supply pipes, but with large supply mains this may be consid- 
erably reduced. 

By using large and well-covered pipes satisfactory results will be 
obtained. Too frequently, in order to reduce the cost, pipes of too 
small diameter are used, especially for indirect steam heating. 

The supply pipes in the basement of a schoolhouse should be 
well covered with a neat non-heat-conducting covering, and although 
the first cost will be increased, yet the results therefrom will fully 
compensate for the additional expense. 

Care should be taken that the steam-pipes are properly pitched, 
dripped and valved in order to secure free and noiseless circulation 
and return ; that they are properly supported on roller pipe hangers 
and proper allowance made for expansion and contraction. 

The main return pipes should be provided with proper check 
valves and shut-off s. Valves for controlling vent-flue heating should 
be placed in the basement. Every radiator, heating coil or stack 
should be fitted with a supply valve, return valve and automatic air 
valve properly located. Gate or angle valves are to be preferred to 
globe valves. Overhead pipes for heating the basement should be 
properly valved, pitched and of such form as to provide for expan- 
sion and contraction, and hung from the floor timbers of the first 
story with securely fastened roller pipe hangers about every 
eight feet. 

Where circulation pipes are placed on the walls the pipes 
should be well straightened and secured to the wall by hook and 
expansion plates, fastened to wooden strips placed not more than 
ten feet apart, and ample provision made for expansion and con- 
traction. 

Rising main and return pipes should be straight and parallel, 
properly valved and dripped, and where pipes pass through floors 
they should be incased through the full depth of flooring and ceiling 
in tin tubes with Jlanged iron plates screwed to the floor, and with 
iron ring plates or flanges securely fastened to the ceiling. Where 
pipes pass through wooden partitions tin sleeves and flanged plates 
should be used and if through brick walls, metal collars should be 
provided. Where practicable, return pipes should be laid in a 
properly-graded brick trench having a covering of cast-iron plates 
or bluestone flagging. 

Where several vertical return pipes enter the main return they 
should in all cases be carried well below the water-line in the boiler 
before they unite into one pipe. 



THE SCHOOL HOUSE. 95 

By proper arrangement of pipes and radiators in a low-pressure 
gravity return system the condensation may be easily and noise- 
lessly returned to the boiler without the use of traps or pumps. 

For piping connections it is advisable to use eccentric fittings. 

A two-pipe, low-pressure, gravity return system of steam- 
heating is to be preferred for schoolhouses of small or moderate 
size. In large buildings a double mechanical system (one having 
a fan supply and fan exhaust), or a combination of fan (or plenum) 
supply and gravity exhaust, is to be preferred. 

Where a mechanical system is used, the exhaust from the engine 
should also be used for heating. A mechanical system will require 
the use of fans, engine, pumps or traps, governor, tanks, steam 
separator, reducing valves, exhaust head, vapor pipe, etc. 

A blow-off tank, properly connected with a dry well or sewer 
and properly trapped, should be provided in all cases where 
practicable. A valve or cock should be provided at the lowest 
place in the system to draw off the water when desired. 

Radiators. 

In the earlier attempts to ventilate school buildings by indirect 
radiation many failures occurred on account of an insufficient 
amount of radiation and improperly locating and casing it ; not 
allowing sufficient space between the sections for a liberal quantity 
of air to pass, too small steam supply and return pipes, and not 
providing adequate means for regulating the temperature of air 
passing the radiators. 

It has been found in actual practice (and the schoolrooms in 
Massachusetts are now generally heated accordingly) that to 
secure the best results under varying conditions of temperature and 
wind 400 square feet of cast-iron radiating surface should be 
supplied for an ordinary schoolroom 28 by 32 by 12 feet, if 
situated where there are two cold exposed walls and where ample 
window space to give good light is provided. 

This should be divided into three stacks, one of 100, one of 140 
and one of 160 square feet; or one of 120 and two of 140 square 
feet each, each stack to be separately piped and valved, in order 
that one, two or three sections may be used as needed, according to 
the outside temperature. The 100 feet section should be placed 
nearest the uptake warm-air flue. 

Where there is but one exposed wall, and on the southerly side, 
380 square feet may be used and divided into three stacks, one of 
100 and two of 140 square feet each. 



96 THE SCHOOL HOUSE. 

Cast-iron radiators having an extended surface, and with not less 
than one-half-inch space between the ends of the pins or ribs of the 
several sections, are now generally used in Massachusetts school- 
houses. 

While coils or radiators made of steam-pipes are the most efficient 
radiating surfaces, yet, on account of the cost and the facility of 
constructing the indirect radiator stacks, cast-iron is now generally 
used with gravity systems. 

It is better to use a deep radiator than to double bank or place 
one section above another. Cast-iron extended surface radiators 
having 20 square feet of radiating surface per section give very 
satisfactory results. 

The sections are 36 inches long, 15^ inches high, and connected 
four inches from center to center of the sections, tapped for. two- 
inch supply and return pipes, and have right and left nipple connec- 
tions. The air-valve measures f of an inch. 

When more than one school-room receives its warm air through 
radiators in the same cold-air room the radiator stacks for each 
room should be separated by galvanized-iron divisions extending 
about 20 inches below the bottom of the stacks. Where this is not 
done, and two or more rooms receive air from the same cold-air 
room, the results are very unsatisfactory, as one room may receive 
much more than its fair proportion of heat and air at the expense 
of another. The galvanized-iron casings for indirect radiators 
should be made on number 20 or 22 gauge iron, and be well 
stiffened at the edges and corners. 

When rooms in different stories of the building receive their air 
supply from the same cold-air room the radiators for the first story 
should be placed nearest the cold-air window, in order that they 
may have an advantage in receiving air in preference to the rooms 
in the second or third stories. 

The supply and return pipes for the indirect radiators should be 
well protected in all cases where they come inside the cold-air 
rooms with first-class pipe covering. <• 

The valves should always be placed outside the cold-air 
rooms. 

The air-valves give better results when placed in the quarter 
turn or elbow where the return changes to a downward direction 
than when placed in the radiator itself, as is usually done where 
direct radiators are used. 

The bottom of the radiators should not be cased, but left entirely 
open, as much more even distribution of air is obtained. 



THE SCHOOL HOUSE. 97 

In the earlier indirect radiator work it was customary to inclose 
the radiators on all sides and bring the air in at one end of the 
bottom of the casing, taking it out at the top of the opposite end. 
This does not give as good results, or utilize the whole of the 
radiator surface, as well as when the bottom is left entirely open 
and a cold-air room is provided. Under some conditions, when 
the first method is used, there is a reversed or back draft, and the 
writer has frequently found warm air going out of the building 
through what was intended to be the cold-air supply opening. 

There are many patterns of direct radiators in use, each of which 
is claimed by the manufacturer to have various good points. Better 
results are obtained when a tall radiator is used than when the 
stack is made long and low. 

In Part II. is shown a direct-indirect radiator, designed by the 
late John T. White, which has been successfully used where a full 
supply of air is not required by indirect radiators. It is cased and 
inclosed in a manner that insures a better utilization of heat than 
is possible with the common style of direct-indirect radiators. 

In many schoolhouses lines of 1 ^-inch steam-pipe are placed on 
the outside walls of the rooms, and are used at night and before 
the school session opens to quickly warm the rooms. In rooms 
occupied but a part of the time, such as assembly halls and labora- 
tories, etc., this is a good provision and saves fuel, but they should 
not be used in schoolrooms while schools are in session. 

Direct radiators are often used to good advantage in schoolhouse 
corridors and in teachers' rooms. 

In basement rooms the heating should be by overhead lines of 
1^ inch pipe, unless a room is used as a manual training room or 
for a similar purpose, in wdiich case a moderate supply of air from 
indirect radiators can be introduced near the ceiling. 

In using wall or ceiling pipes special attention should be given 
to properly provide for expansion and contraction. 

There should be at least two feet distance between the bottom of 
the radiators and the water-line in the boiler to secure a good 
return of the condensation from the radiators. If a greater distance 
can be had it will be better, and danger of filling the radiators with 
water will in a great measure be prevented. The writer has seen 
cases where an otherwise well-designed system of heating has been 
spoiled by not allowing sufficient distance between the bottom of 
the radiators and the water-line in the boiler. 

A method is shown in Part II. of arranging radiators to be used 
as foot-warmers and for warming the corridors. These stacks are 



98 THE SCHOOL HOUSE. 

usually made up of 120 square feet of cast-iron extended surface ra- 
diators, cased in galvanized iron and hung from the basement ceiling. 
Very satisfactory results are obtained when two lines of 1^ inch 
steam-pipe are placed near the floor in the corridor and under the 
clothing racks. 

An Approximate Rule for Estimating the Amount of 
Indirect Radiation 

For a fifty-seat schoolroom of the ordinary size (28 by 32 by 12 
feet) with a gravity system of heating and ventilation, using a good 
indii*ect radiator with ample flues, etc., and natural draft, is as 
follows : 

50 (number of pupils) X 30 (cubic feet of air per pupil per 
minute) = 1500 (cubic feet of air per minute). 

1500 (cubic feet per minute) X 60 (minutes per hour) =90,000 
cubic feet of air supplied per hour. 

Air at zero to be warmed 105 degrees F. 90,000 (cubic feet) 
X 105 (degrees) =9,450,000 cubic feet of air warmed one degree. 
9,450,000 (cubic feet) -r- 50 (cubic feet warmed one degree by one 
heat unit) = 189,000 heat units. 189,000 (heat units) -r- 1,000 
(heat units available per pound of steam) =189 pounds of steam 
condensed to water. 189 X 2=378 square feet of radiation. In 
actual practice from 380 to 400 square feet of cast-iron indirect 
radiation is used per room. This allowance is made on account of 
overrating the square feet of surface in radiators by the manufac- 
turers, for air leakage in rooms and to meet the requirements in 
exceedingly cold weather. 

While this may not be an approved scientific method of calcu- 
lating indirect radiation, and may by some be called a " rule of 
thumb," yet in actual practice it has giveii excellent results and 
may be considered as safe as some more scientific and theoretical 
formulas. 

Automatic Heat Control. 

Systems of automatic heat control have been installed in a con- 
siderable number of schoolhouses, especially in large buildings, 
and if they can give the results claimed for them they will be of 
great service. Unfortunately, in many cases they have not proved 
satisfactory, and in a short time complaints were made that the 
expected results had not been obtained. 

The first attempts to automatically control mixing dampers were 
generally complete failures. A device that opens wide or closes 



THE SCHOOL HOUSE. 99 

tight the mixing damper changes the temperature from all warm 
to all cold air, and uncomfortable drafts are the result. 

The writer has seen cases where the temperature of the incoming 
air was changed from over 100 degrees F. to less than 30 degrees 
F. in less than four minutes when the mixing damper was auto- 
matically operated. When the damper was again moved the 
temperature would rise to the high point in but little over five 
minutes. This was especially noticed when a strong wind was 
blowing into the cold-air room. When the mixing damper is 
moved to entirely shut off the warm air, except what little leaks 
through the narrow spaces on the sides and top of the mixing 
damper, the radiators, if steam is used, soon become cold, and the 
cold air from outside passes up directly into the schoolroom. With 
furnaces the results are not any more satisfactory. 

When the mixing damper is moved slowly by the automatic 
control, but is opened wide or fully closed, the results are not 
satisfactory. 

The managers and agents of some automatic heat-controlling 
systems frequently guarantee that the mixing-dampers or the valves 
controlling the heat supply steam-pipes will be operated by one 
degree or less change of temperature, as indicated by the ther- 
mometer attached to the thermostat. While this is true in many 
cases, yet it does not give satisfactory results at all times. When 
the cold air is admitted by the mixing-damper, or the steam-valves 
to the indirect radiators are shut, the radiators are soon cooled and 
uncomfortable drafts are felt, and as the thermostats are often 
placed where they are not easily and quickly acted on by the 
incoming air, the drafts continue. After the steam has been 
again turned on by opening the valves, time is required for the 
radiators to again become warm enough to give off sufficient 
heat to properly warm the incoming air, the cold drafts will 
continue until the incoming air has changed the temperature at 
the thermostat enough to operate the valve or damper-controll- 
ing device. This is often several minutes after the valves have 
been opened. 

Most of the automatic heat-controlling devices are of delicate 
construction, and the writer has seen cases where an accumulation 
of lint or fine fibers has caused the apparatus to become 
inoperative. 

Where automatic control has been used on direct radiators, or 
where a combination of automatic and hand-control has been used 
on the valves of different sections of the indirect radiators, more 



100 THE SCHOOL HOUSE. 

satisfactory results have been obtained than when used on mixing- 
dampers. 

By dividing the amount of indirect radiation for a school-room 
into three sections and using hand valves on two, and automatic on 
one section, better results are obtained than where the automatic is 
used on all three sections. 

Automatic control is sometimes used on the supplementary 
radiation in mechanical systems where fans or blowers are used. 
If it is to be used in a mechanical system the results will be better 
if the primary coils or stacks are provided with all or nearly all 
band-controlled valves, and the automatic used on the supple- 
mentary coils or stacks or direct radiators or wall coils, if such 
are provided. 

When used on hot-water radiators the change of temperature is 
not as rapid as with steam radiators. 



CHAPTER VII. 



FURNACES. 



THE use of furnaces for heating and ventilating school 
buildings should be confined to small buildings not' 
exceeding eight rooms. 

In large buildings the number of furnaces required will occupy 
so much of the basement and there will be so many fires to attend 
to that a steam-heating apparatus can be more advantageously 
installed. 

When furnaces are used in school buildings or places of assem- 
blage they should be located where the warm-air flues or ducts will 
be as nearly perpendicular as possible. Long and nearly hori- 
zontal runs of pipe should be avoided. 

It is advisable that schoolhouse furnaces should be of heavy 
castings having as few joints as possible. There are several makes 
of furnaces specially designed for schoolhouse heating and of extra 
large size. 

A cast-iron furnace having a fire-pot of 34 to 35 inches diameter 
should be provided for two school-rooms of the ordinary size 
(28 by 32 by 12 feet). 

Attempts to use smaller furnaces or to heat more than two 
ordinary size school-rooms from one furnace have resulted in 
failures to give the required amount of heat, and now it is seldom 
that a contractor intending to do good work will attempt to heat 
and ventilate more than two schoolrooms with one furnace, even if 
the furnace is of the largest kind manufactured. 

In selecting a furnace, one with a nearly straight-sided fire-pot is 
to be preferred to one that has sloping or tapering sides. In the 
latter case the accumulation of ashes at the side of the fire-pot 
retards the passage of heat, and the fire is not as easily cleaned as 
when the sides are nearly perpendicular. 

Furnaces provided with triangular revolving grates are to be 
preferred to those having oscillating ones, as the triangular grates 
will cut the ashes and clinkers and remove them more effectually 
than will other patterns of grates. 



102 THE SCHOOL HOUSE. 

Wrought -iron or steel-plate furnaces with fire-brick lining have 
not given as satisfactory results as those of cast-iron which have a 
good thickness of metal. 

It is claimed for wrought -iron furnaces that they do not allow 
gas t6 escape through the metal, and that it will through highly- 
heated cast-iron. 

While it is true that under some conditions gas will to a limited 
extent escape through highly-heated cast-iron, yet with an ample 
supply of air passing to the school-rooms and a large furnace of 
heavy castings, not overheated, the amount of gas escaping will be 
so very small that it may be practically disregarded. 

The escape of gas through heated cast-iron is more a matter of 
advertising the special advantages claimed for some furnaces than 
of real danger to the occupants of a school-room. 

It is essential, however, that there be as few pieces as practicable, 
and that the joints be made as tight as possible. 

By proper attention to the draft and check dampers the amount 
of escaping gas can be reduced to a point at which no ill effects 
can be observed. 

If it is suspected that gas is escaping from the combustion 
chamber into the warm-air supply for the room, an old rubber or 
a leather shoe may be thrown into the fire, and when the shoe is 
well ablaze, all the dampers and drafts being closed, it will soon 
be determined whether or not gas is passing into the room. The 
odor of the old shoe will be noticeable at the warm-air inlet if any 
considerable amount of gas is coming in. 

Several designs of cast-iron furnaces made of vertical sections 
with extended surfaces, and held together with bolts through 
flanges of the sections, have been used in school buildings ; but they 
are not a desirable type, as there are too many joints, some of 
which may warp and open up a passage for the unconsumed products 
of combustion to pass through and mingle with the air supply for 
the schoolrooms. This class of furnace is now seldom installed in 
Massachusetts schoolhouses. 

The writer has seen a number of these furnaces, which by exces- 
sive firing by the janitors have so warped at the flanges and where 
the bolts have so rusted or been destroyed by heat, that openings, 
sometimes one-half inch or more wide, have been made through 
which the unconsumed products of combustion have passed in a 
sufficient quantity to badly contaminate the air in the school-rooms. 

Some cast-iron furnaces also have a radiator attachment of thin 
sheet-iron or steel which in a few years will become corroded 



THE SCHOOL HOUSE. 103 

sufficiently to open large holes for the escape of gas. Where these 
radiator attachments are used the sheet metal should he of sufficient 
thickness to last as long as the cast-iron fire-pot. 

In installing a furnace for schoolhouse heating special attention 
should be given to having sufficient space between the heating 
surface and the casing to allow the passage of a large quantity of 
air at a moderate temperature, rather than to heat a small quantity 
to a high temperature. 

It is advisable to use brick-set furnaces in schoolhouses instead 
of the metal-cased portable type generally used for dwelling-house 
heating, which usually have an insufficient space between the 
casing and the fire-pot. When the portable type of furnace is 
used in schoolhouses a special and large casing'should be provided. 

Smoke-pipes for furnaces should be of ample size and as short 
as possible to reach the chimney smoke-fine, having as few turns 
or elbows as practicable, and fitted with one or more dampers to 
regulate the draft. 

When soft coal is burned, the ordinary size schoolhouse-furnace 
smoke-pipe should be at least one inch larger diameter than when 
hard coal is used. 

Where it becomes necessary to take the smoke from two furnaces 
into one chimney flue, which is not a desirable arrangement, the 
pipes should be united by a breeches connection into one large 
pipe before it e'nters the chimney, anck each furnace smoke-pipe 
should have its own damper. 

A pit should be provided under the furnace which should be at 
least two feet deep and equal in width to the diameter of the 
furnace casing. This will allow the air to circulate around the fire- 
pot and will more effectively distribute it against the heated surface 
of the fire-pot. When, as has frequently been the case, the air is 
admitted through an opening in one side of the furnace casing and 
nearly opposite the fire-pot, the results are not satisfactory, and 
but part of the heated surface is utilized in the most effective 
manner. 

The air for mixing with the air from the furnaces for regulating 
the temperature of the school-room should never pass under the 
furnace, but should be entirely outside the space between the fire- 
pot and casing. 

When the air for mixing is taken under the furnace the result 
will surely be a failure to secure proper temperature for the air 
entering the school-room. The air will follow the line of least 
resistance, which is up near the heated surface of the fire-pot, and 



104 THE SCHOOL HOUSE. 

will not pass under the furnace and into the space intended for it 
to reach the mixing-valve. 

When the warm air is shut off by the mixing-valve it will be 
heated and expanded in the hot-air chamber, and will back down 
and out into the space intended for the cold air for mixing. It 
will, when the mixing-valve is open for warm air, follow the line of 
least resistance, and the school-room will become overheated when 
there is a strong fire in the furnace. In moderate "weather under 
such conditions it will be impracticable to furnish the required 
amount of air without uncomfortably overheating the school-room. 

A furnace smoke-pipe should never pass through a cold-air room 
when possible to avoid doing so. In case of a smoke-pipe rusting 
and opening holes in the pipe, or if the pipe is not well and tightly 
jointed, there is liability of the unconsumed products of combustion 
passing into the school-rooms. The cold air also has a tendency to 
reduce the heat of the escaping gases and retard the draft. 

The writer has seen cases where the smoke-pipe was intention- 
ally twisted and made into "what may have been intended to be 
similar to a trombone coil, for the purpose, as alleged, of utilizing 
.the waste heat in the smoke-pipe for warming the air in the 
cold-air room. 

The result was, however, that it made a good condenser, and 
the condensed smoke and gases dripped down through the joints in 
the pipe into the cold-air room and assisted in contaminating the 
fresh air in addition to what was done by the gas escaping from 
the combustion chamber through openings between sections of the 
furnace. The condensation also assisted greatly to destroy the iron 
of the smoke-pipe. 

The furnace should be placed below the school-room rather than 
under a corridor or clothing room, in order that the warm air may 
pass up the front side of the heat shaft instead of on the back, and 
thus avoid uncomfortable drafts in the school-room. 

The cold air for mixing should always pass up on the rear 
side of the heat shaft. 

When for structural reasons the furnace must be placed other 
than under the school-room, the furnace should be placed low 
enough to enable the cold air for mixing to be taken over the top 
of the furnace casing or setting and to enter the heat shaft on the 
rear side. The proper location of the furnace is a matter that 
should be carefully considered, as nothing will contribute more to 
obtaining satisfactory results as to temperature than will its proper 
location with relation to the warm-air flues. 



THE SCHOOL HOUSE. 105 

Pipes for conveying air to floor registers in corridors or clothing 
rooms should not be taken from the warm-air chamber of a furnace 
when the warm air for the school-rooms is taken into the room 
above the floor. Where this is done the results are not satisfactory 
as the air, instead of passing to the floor registers, will frequently 
be carried up the warm-air flues into the school-rooms, and a 
reversal of the air current will result. This will happen whenever 
the air supply for the furnace is checked or partly shut off at the 
cold-air opening into the fresh-air room. The air will be taken 
from the corridor or clothing-room to the school-room instead of 
from the furnace to the corridor. 

A liberal sized cold-air room should always be provided for 
furnaces in schoolhouses. It will to a great extent prevent back 
drafts by suction of the wind outside, and will give a much better 
supply of air under all conditions than will the ordinary cold-air 
box. 

The windows in the cold-air room should be hinged from the 
top and the opening be covered with a stout wire grill or netting. 

If heat is required for corridors or small rooms it is much better 
to provide a small and separate furnace for this purpose, providing 
steam cannot be used. 

In the best and most satisfactory work now being done in Massa- 
chusetts, where furnaces are used for heating class-rooms, a small 
steam boiler is used to furnish heat for the vent-flues and also for 
warming the corridors and small rooms. 

Twin connected furnaces are sometimes installed in schoolhouses ; 
but the results obtained are not as satisfactory as where each 
furnace has an independent setting. 

The distribution of air is not always good and depends upon 
which furnace is heated, as is the case when only one furnace is 
in use in moderate weather. 

When a fan is used and both furnaces are heated, the results are 
much better than by a gravity system using only one of the twin 
furnaces at a time. 

The use of a combination of furnace and hot-water heating is 
not recommended for schoolhouses. While often giving satisfac- 
tion in a dwelling-house, the conditions existing in a schoolhouse 
are not such as to justify the use of a hot-water attachment in the 
furnace. 

It frequently happens that during cold weather the janitor will 
allow the fires to go out between the close of the Friday p.m. 
session and the opening of the Monday a.m. session, or that during 



106 THE SCHOOL HOUSE. 

the winter vacation the fires will not be kept up. In such cases 
the water attachment may become frozen and pipes or radiators 
burst. 

Where electric power is obtainable at a reasonable price a com- 
bination of fan and furnace may be used, and excellent results 
obtained, especially in mild weather. 

A good sized disk fan run at a comparatively low velocity, if 
properly located between the cold-air room and furnace, will give 
very satisfactory results and can quickly warm the building by 
rotating the air through it before the opening of the school session. 

Where electric power is not easily obtained a gas engine, and in 
some cases a water-motor, has been used to drive the fan. Neither 
of these is as satisfactory as electric power, especially in small 
buildings. 

The noise and the escape of the products of combustion into the 
building are serious objections to the use of a gas engine. 

The cost of water in cities and towns having a water supply 
system is such as to practically prohibit the use of the water-motors 
for running fans. 

Stack Heaters. 

When steam is not available for heating vent-flues, a stove or 
small furnace called a " stack-heater" is used to raise the tempera- 
ture in the vent-shaft and cause a good outflow of foul air. This 
stack-heater is usually placed in the basement so that it may be 
easily tended and to prevent the annoyance of ashes and dirt on the 
schoolroom floor. The air from the first story rooms is brought 
down in galvanized-iron ducts (or sometimes brick ducts) and 
enters the vent-shaft below the stack -heater. 

When a stack -heater is used the foul air from the schoolrooms is 
taken out through one common vent-shaft having a cross-sectional 
area of 20 square feet for four 50-seat schoolrooms, which are as 
many rooms as it is advisable to vent through one shaft. The two 
rooms in the second story should be vented directly into the 
common shaft. 

A stack-heater, having a fire-pot about 22 inches in diameter 
and grate 20 inches in diameter, is generally used to ventilate a 
school building where four school-rooms and two corridors are 
vented into the same shaft. 

A stack-heater for sanitary closets in school buildings containing 
up to eight rooms, and with a 16-inch diameter fire-pot and 14- 
inch grate, is commonly used in the sanitary vent-flues. While 



THE SCHOOL HOUSE. 107 

smaller grate surface may theoretically be used in stack-heaters, yet 
with too small a fire-pot the fire is liable to go out for want of 
proper attention by the janitor. 

The stack-heater should be placed so that the air for furnishing 
the draft for the fuel is taken from outside the shaft. 

When the stack-heater is placed entirely within the vent-shaft 
and receives its air for draft from within the shaft and is tended 
through a door in the shaft, the results are not satisfactory. 

Where separate vent-flues are provided from each of several 
rooms it is not practicable to use a stack-heater, and steam heat 
must be employed. 



CHAPTER VIII. 



JANITORS. 



SUCCESS or failure in obtaining satisfactory results with a 
well-designed system of heating and ventilation often 
depends upon the care and good judgment exercised by 
the janitor or engineer having charge of the apparatus. 

Complaints have frequently been made that the heating and 
ventilation of a school building were not satisfactory; that the 
rooms were too warm or too cold ; that uncomfortable drafts were 
felt ; that the air was bad, etc. 

On inspection, these complaints were often well founded, and 
on looking for the cause it was very frequently discovered to be the 
fault of the engineer or janitor in charge, and not of the apparatus 
installed in the building. 

A janitor or engineer who is negligent, or not informed as to the 
proper way of operating the apparatus under his control, can 
easily give a well-designed and a properly-installed system a 
bad name. 

If heating and ventilating engineers and contractors who install 
systems in school and public buildings will see that the engineer or 
janitor is properly instructed as to his duties when first taking 
charge, they will find it greatly to their advantage ; not only as to 
the reputation their work will have, but they may be saved expense 
in responding to calls to come and see what is the matter with 
the apparatus. 

Printed instructions provided by the contractor or engineer who 
designed the work, if posted in the boiler or furnace-room, will 
more than pay the expense of printing and posting, and will 
save annoyance. 

A janitor who understands the system and properly manages it 
will not only give better satisfaction to the school authorities, but 
will in many cases make a considerable saving in the expense 
of operation. 

An incompetent or lazy janitor may cause an excessive waste 
of fuel and perhaps serious damage to the apparatus under his 
charge. 



THE SCHOOL HOUSE. 109 

A janitor in a school or public building should be able to pass 
an examination as to his fitness and ability to manage the modern 
appliances for heating and ventilating a schoolhouse or public 
building. 

More is required of a janitor than the ability to shovel coal into 
a furnace or under a steam-boiler, or to see that a proper amount 
of water is in the boiler. Good judgment and a thorough knowl- 
edge of the apparatus is essential. 

Besides regulating the fires properly by having good and clean 
fires in cold weather and light fires in moderate weather, and, with 
a steam-heating system, seeing that the proper amount of radiation 
is in use, it is of the utmost importance that the inlets for fresh 
air, the mixing-damper for regulating the temperature of the air 
supplied to the class-rooms, the heat or fans for the ventilating 
ducts, and the dampers for regulating the outflow of foul air, 
should be properly understood and managed. 

In a mechanical (fan) system care should be taken that the fans 
are run at a proper speed and at the proper time. 

It is very important that the windows admitting air to the cold- 
air rooms, where the indirect radiators or furnaces are located, are 
properly opened or partly closed, as may be required by the con- 
stantly varying conditions of temperature and wind. These 
windows should be hinged at the top and open inward in order 
that the air may be deflected downward and distributed through the 
cold-air room. 

The stacks of indirect radiators or the furnace should never 
be placed so close to the window that the window cannot be 
opened to its full capacity. When a gravity system is used the 
windows in the cold-air rooms should have an opening equal to 
the combined area of the several ducts leading from the cold-air 
room. 

With a mechanical system in a large building the area of these 
windows may be less than in a gravity system. 

In mild weather and -when there is but little wind they should 
be kept wide open during the school session; in very cold or 
windy weather they should be partly closed ; but under no 
circumstances should they be entirely closed when school is in 
session . 

If opened too wide when a strong wind is blowing into the cold- 
air room, more air will be supplied than is required or can be 
properly warmed, and uncomfortable drafts will be felt in the 
school-rooms. 



110 THE SCHOOL HOUSE. 

If closed too much, a sufficient supply of fresh air will not be 
furnished and the air in the school-rooms will be vitiated to an 
objectionable degree. 

When on the leeward side of the building they should be opened 
wider than when they are on the -windward side. 

Each window in the cold-air rooms should be provided with a 
stout cord or chain and pulley and means for fastening the same, 
in order that the window may easily be opened or closed to any 
desired position". 

It is also advisable to hold the window in the desired position 
and not allow it to fly up or down by the action of the wind. 
This can be done by another cord or chain. 

Mixing-valves or dampers are placed in the fresh-air ducts 
which lead to the several rooms, by means of which the air is 
allowed to pass through the stacks of indirect radiators or along 
the heating surface of the furnace, or is caused to by-pass without 
going through the heaters. 

By the use of mixing-dampers the temperature of the air supplied 
to the school-rooms can be regulated without materially reducing the 
supply. 

When valved registers are used and the room becomes too warm 
the heat is shut off as is also the supply of air at the same time. 

The teachers as well as the janitor frequently operate the mixing- 
valves and dampers, and should also be instructed in their use. 

It often happens that when the school-room becomes overheated 
the chain operating the mixing-valve is pulled in such a manner as 
to almost entirely shut off the warm air and turn on the cold air. 
Cold air is then admitted to the room and uncomfortable drafts are 
caused, then when the room has become too cool the chain is 
moved in the opposite direction and the room is soon overheated 
again. If this is continued the teacher or janitor will be kept busy 
trying to keep the room at a comfortable temperature. 

If, however, when the temperature of the room begins to rise or 
fall below the desired point (68 to 70 degrees F.) the mixing- 
damper chain is moved but a little at a time — say from one-half to 
one inch — there will be little difficulty in maintaining the desired 
temperature if the fires and the windows in the cold-air rooms are 
properly managed. The mixing-valve, after having been once 
properly adjusted, may not require to be moved during the whole 
or greater part of the session. 

Two or three pieces of thin or narrow ribbon — about one- 
quarter of an inch wide and about ten inches long (red, white and 



THE SCHOOL HOUSE. Ill 

blue would be appropriate colors) tied into the wire grill at the 
warm-air inlet, about two-thirds the distance up from the bottom 
to the top and in the center of the wire grill, will be of great assis- 
tance to the teacher in determining whether or not a proper amount 
of fresh air is being supplied to the school-room. 

If the ribbon does not blow out or flutter it will indicate a defi- 
ciency in the fresh-air supply. 

A metallic thermometer about four inches in diameter, which 
has an indicator hand, will, if placed on or in the wire grill near 
the ribbon, enable the teacher or janitor to place the mixing-valve 
in the right position. 

As the outflow of air from a room through the exhaust flues or 
ducts is caused, in a gravity system, by the difference between the 
temperature of the external and internal air, and also by the force 
of the wind blowing across the top of the ventilating stack or flue, 
some means of meeting the constantly-varying conditions of tem- 
perature and wind must be provided. 

In a mechanical system provision should be made for regulating 
the flow of air through the several ducts and flues. 

In both the gravity and mechanical systems dampers should be 
placed at the outlet from each ventilated room. 

The heat in the vent-flues should be used in a manner directly 
opposite from that used for warming the rooms. The greater the 
difference between the temperature of the outside and inside air, 
the less will be the amount of heat required in the vent-flues. 

In very cold and windy weather no heat may be needed in the 
vent-flues, and the dampers in the outlets from the rooms may often 
be partly but never entirely closed while school is in session. 

In mild and calm weather the dampers should be wide open and 
heat maintained in the vent-flue heaters. The warmer the weather, 
the more heat will there be required in the vent-flue heaters. 

Pieces of ribbon similar to those on the warm-air inlet should 
be provided for the outlets, but they should be placed on the inner 
side of the grill. If they flutter into the duct it will indicate an 
outflow of air from the room. If they blow back or rest 'against 
the grill it w r ill indicate a reversed draft or no draft. 

In cold weather, after the school session has closed, sufficient 
time should be allowed to flush out the room with fresh air. 

The dampers at the outlets should then be closed and the heat 
in the vent-ducts shut off. 

Leaving the dampers in the vent-ducts open at night will cause 
a waste of fuel and unnecessary cooling of the rooms. 



112 THE SCHOOL HOUSE. 

In warm weather, when no heat is supplied by the warm-air 
inlets, the dampers may remain open at night. 

After school has been dismissed for the day and the class-rooms 
have been flushed out with fresh air from the warm-air inlets the 
windows admitting air to the cold-air rooms in the basement should 
be closed, as should also the dampers in the vent-flues. The rotat- 
ing registers in the floor above the cold-air rooms, as "well as the 
doors from the several class-rooms, should then be opened and the 
air rotated through the building by means of the indirect radiators 
or furnaces. The fires can then be banked and checked for the 
night. 

In cold weather, if direct radiation has been provided in the 
class-rooms in addition to the indirect radiation, the direct radiation 
should be turned on and kept on till a short time before the opening 
of the morning session. 

If plenum fans are used they should be started in season to 
thoroughly warm the building by rotating the air before the opening 
of the morning session. 

The direct radiation in class-rooms should not be used while 
school is in session, unless the class-rooms cannot be heated 
without it. 

The heat in the sanitary vent-flues should be kept up at all times, 
except perhaps in very cold and windy weather. 

The dampers in the corridor vents should be closed at night. 

Care should be taken not to open the windows in the sanitary 
rooms and allow the wind to blow in, as the odors may under some 
conditions be driven out of these rooms into other parts of the 
building. 

It is much better to depend upon the sanitary vent-flues to 
properly ventilate these rooms by drawing the odors from the room 
through the sanitary closets and urinals. 

Liberal use of water should be made for flushing the sanitary 
fixtures. 

The janitor should be in the building in the morning in season 
to have the building properly heated and the ventilating apparatus 
in good working order before the school session opens. 

After cleaning and properly starting up the fires he should open 
the windows admitting fresh air to the cold-air rooms and properly 
adjust them to meet the existing conditions of wind and outside 
temperature. He should then close the rotating registers, open 
the vent dampers to the proper degree and % close the class-room 
doors. 



THE SCHOOL HOUSE. 113 

When the large boilers in a steam heating system are in use the 
steam for heating the vent-flues should be supplied from that 
source ; but when the large boilers are not in use, or with a furnace 
system of heating, the small boiler, usually called the " summer 
boiler," should be used. 

The doors, tvindozus and transoms should be kept closed while 
school is in session in order to obtain the best results front the 
heating and ventilating system, and to secure a proper circula- 
tion of air in the rooms. 

Springs or door-checks, if provided on all outside doors, will 
soon repay the extra expense by the saving of coal. 

Janitors should be held to a strict accountability that the heating, 
ventilating and sanitary appliances in the buildings under their care 
are managed in a manner to secure the best results. 

While they should not be blamed for improperly designed or 
constructed apparatus, yet they should be required to secure the 
best possible results obtainable from the apparatus under their 
control and to keep the same in good condition. 

The janitor should see that the boilers or furnaces are left in 
proper condition at the end of the school term. If a mechanical 
system is used all parts of it should also be attended to. If any 
defects develop or accidents occur to the boilers, piping, valves or 
other parts of a steam-heating system, or in the furnaces or stack- 
heaters under his charge, the proper authorities should at once be 
notified in order that the required repairs may be made promptly. 

All accumulations of ashes or rubbish should be promptly 
removed from the building. No inflammable or combustible 
material should be placed or allowed to accumulate in any closet 
or near a stairway or means of exit. 

Where the pupils use paper instead of slates for their work, as 
is now generally the case in Massachusetts schools, care should be 
taken that it be promptly burned or removed from the building, 
and not allowed to accumulate in the basement or in any closet. 

All the rooms in the building should be thoroughly and frequently 
swept and dusted, the sanitary rooms and fixtures washed and 
disinfectants freely used if required. 

Where outside sanitary buildings are used they are often found 
to be in a very bad condition. The janitor should be required to 
inspect all the rooms and outbuildings under his charge at least 
once a day and should be held responsible for their cleanliness. 
He should investigate all cases of misuse of the sanitaries and 
report to the principal of the school or the school committee. 



114 THE SCHOOL HOUSE. 

The playgrounds or yards should be kept in a neat condition and 
not become the repository of rubbish of any kind. In winter the 
janitor should see that all walks and entrances are properly freed 
from snow and ice, and that the basement doors are opened a 
reasonable time before commencement of the school session. 

The average annual amount of coal burned in well-heated and 
ventilated school buildings in Massachusetts is about ten tons per 
class-room. This includes the basement, corridors and small rooms 
in an ordinary schoolhouse. ' 

Where much in excess of this amount is used, unless in a build- 
ing in a very exposed location, or one badly constructed, or where 
the system of heating and ventilation is badly designed, it is fair to 
presume that the janitor has not been careful in managing the 
fires. 

Where, as is sometimes claimed, only seven or eight tons of 
coal are burned per year, it will be found that the air supply has 
been restricted to an amount below what is required for good 
ventilation. 

Some janitors, either to make less work for themselves, or to 
establish a record for economy in fuel, shut off the fresh-air supply, 
or fail to maintain proper heat in the vent-flue heaters. 

In cities and large towns much better janitor service would be 
obtained if a competent "head janitor" was employed and if it 
was made a part of his duty to see that the other janitors were fully 
instructed in and properly performed their duties. 

It is false economy to employ, as is often done, an incompetent 
or lazy janitor because he can be hired cheap. 

It is not advisable that one janitor should have charge of several 
buildings, sometimes situated at a considerable distance from each 
other. 

Very frequently janitors do not receive suitable compensation for 
their work. This is more often the case in small towns than in 
cities. Fair compensation should be given for intelligent and faith- 
ful service. 

The following extracts from a paper read at the twelfth annual 
convention of the International Convention of Factory Inspectors 
at Boston in 1898, by Thomas Hawley, State Inspector of Boilers 
and Examiner of Engineers and Firemen, contain many facts which 
it would be advisable for school committees, superintendents and 
principals of schools to carefully consider : 

" There is another class of boiler that has received considerable attention 
from the department ; namely, those in schoolhouses and public buildings. 



THE SCHOOL HOUSE. 115 

While a very large number of firms and manufacturers have sadly neglected 
their boilers and allowed them to go without inspection, those who control 
the steam plants of large heating plants seem to have been more guilty in 
this respect Ver\ T few school boilers have been found upon which it was 
not necessary to order extensive changes to make them safe to be run. In 
some cities many of the boilers have been punctured with a blow from the 
light hammer each inspector uses. It has been the policy of the department 
to have the changes made and the boilers replaced or made safe without let- 
ting the facts be publicly known because of the possible alarming of parents, 
and very many boilers have thus been repaired without the pupils or parents 
knowing or suspecting that they had been near a dangerous boiler. The 
reason for this neglect seems difficult to understand. It may arise from the 
fact that in very many places the condition of the boilers is cared for by the 
public buildings department or committee of the city or town, and the boilers 
operated and under the care during the year of janitors appointed by the 
school committee. Each tries to put as much of the work as possible 
upon the other, or at least such would seem to be the case. I have found 
boilers in schools full of mud and deposits up to the hand holes, barrel 
staves, and bricks, tubes nearly filled up with soot, and back connections 
filled clear to the boiler with soot and ashes, hand-hole plates in the boiler 
rusted solid so they had to be broken off, showing the boilers had neither 
been opened for inspection nor cleaned for years. The janitors claim it is 
the work of the building department, and that department claims that if they 
give the school committee a good boiler and that committee provides the man 
to run it, that man should see it was run properly, and properly cared fbr and 
cleaned. Between the two, however, the boiler is not long in getting into 
dangerous shape ; and it has been necessary to condemn school boilers entirely 
in some cases only after a few years' use. I have further found this condition 
to continue even after the inspector's first inspection, when the boiler comes 
to be again inspected, and it is the rule almost rather than the exception to 
find schoolhouse boilers in a dirty uncared-for condition, that shortens their 
lives, develops many defects, and in a filthy condition unfit for a proper inspec- 
tion. The matter, in fact, it seems to me, has been complicated in one way, by 
the inspector making a third person upon whom the others rely, and they will 
now get only such attention as the inspector can give in his annual visit. It 
appears that there is claimed to be objections to having the boilers operated by 
persons not in the employ of the building department, it being claimed that all 
employees in schools should be controlled by the school committee. Of the 
merits of that contention I know nothing, but it does seem as though the two 
together could arrange that the boiler should have proper care and attention, 
or such an important and dangerous part of the school equipment as the 
boiler is should be under the responsibility of the school committee. Prior 
to the enactment of this law, boilers have exploded in schools in this State 
with disastrous results and in spite of the poor care they usually obtain, the 
regular inspection now made does provide a material safeguard. 

" In other instances, too, heating boilers are found much neglected. The 
claim is made that they are run at such low pressure that they cannot explode. 
Yet I have pieces and sections of these boilers in my possession that have 
exploded and very recently, and with disastrous results. Many of these sec- 
tional boilers are of cast iron, and are bad in design, cheap in material, and 



116 the school house. 

improperly set up and inadequately fitted with safety appliances. They 
have been found with devices that bore the name of ''safety-valve," but were 
safety-valves in name only. This most important fitting on a boiler is very 
frequently found altogether inadequate in size and in unfit condition. I have 
within a month taken safety-valves from school boilers which were stuck so 
solid they could not be moved with a hammer, and had become so by neglect 
since the previous inspection." 

The following rules for janitors and firemen having charge of 
low-pressure steam-heating boilers are the requirements of the 
Hartford Steam Boiler Inspection and Insurance Company. 

1. Getting Ready to Start. 
The attendant should see that all joints are properly packed, and that none 
leak on filling the boiler with water. The gauge cocks, water gauge, and 
safety valve should be carefully examined that all are free and in good order. 
All valves in piping and radiators and air valves, should be examined and 
seen to be in order, and that all necessary packing or repairs have been done. 

2. Condition of Water. 
The first dutj' of an engineer when he enters his boiler-room in the morn- 
ing is to ascertain how many gauges of water there are in his boilers. Never 
unbank or replenish the fires until this is done. Accidents have occurred 
and many boilers ruined from neglect of this precaution. 

3. Raising Steam and Management of Valves. 
All steam and return pipes should be closed before fires are started. When 
steam has been raised to working pressure, the steam valves should be opened 
very slowly. After the boiler pressure is established in the pipes the return 
valves can be opened, allowing the water of condensation to flow back to the 
boiler. Whenever necessary to shut off at the boiler or any section of heat- 
ing system, the return or drip valves should be closed first and then the steam 
valves. In letting on the steam the supply or steam valves should be first 
opened and then the return or drip valves. This caution is important. 

4. Low Water. 
In case of low water, immediately cover the fires with ashes, or if no ashes 
are at hand, use fresh coal, and shut the ash pit and open the fire doors. Do 
not turn on the feed under any circumstances or tamper with or open the 
safety valves. Let the steam outlets remain as they are 

5. Feeding. 
When necessary to take fresh water the boiler should be fed as slowly .as 
possible to avoid unnecessary contraction and leakage at joints. 

6. Gauge Cocks and Water Gauge. 
Keep gauge cocks clean and in constant use. Glass guages should not be 
relied upon altogether. 

7. Safety Valves. 
Raise the safety valves cautiously, and frequently, as they are liable to 
become fast in their seats. 



THE SCHOOL HOUSE. 117 

8. Safety Valve, Automatic Regulator, and Steam Gauge. 
Should the gauge at any time indicate the limit of pressure to which the 
regulator is adjusted without its controlling the draft, the regulator should 
be examined and disconnected from the damper or draft door. If the regu- 
lator works quickly and well the trouble is in the damper or draft door, and 
it should at once be cleaned and made to work freely. Should the regulator 
fail to work, or work very slowly, the pipe connection to the boiler is choked 
and should be cleaned. See that pressure gauge, regulator, and safety valve 
agree; in case of difference, notify the company's inspectors. 

9. Clean Plates and Heating Surfaces. 
Particular attention should be taken to keep plates and parts of boilers 
exposed to the fire perfectly clean. Also, all tubes, flues and connections 
well swept. This is particularly necessary in many types of small heating 
boilers with large heating surfaces and small heat passages, as they soon 
foul if neglected. Strict attention to this rule is necessary for full economy 
and capacity of boilers. 

10. Blowing Off. 

If necessary to blow down during the season, the fires should be hauled 
and furnaces and bridge wall cleaned at least two hours before blowing 
down. Allow the boiler to stand until cool before filling with cold water. 

11. Laying up Boilers for the Season. 
Haul fires, clean furnaces, and run off the water while hot. Thoroughly 
clean all heating surfaces at once. Remove hand and man-hole plates, dry 
out water if any remains, and leave the boiler thoroughly clean and dry. 
Drain all water from return drip-pipes. All good systems are provided with 
drip-cocks at lowest point in return pipes for this purpose. During the sum- 
mer see that no water can drip or moisture collect in or around the boiler. 

12. Piping, Radiators, and Settings. 
Mark all joints that have shown signs of leakage and need packing; also 
air-cocks and valves and anything that may need repairs before using another 
season. If repairs are needed to boiler settings see what they are and have 
them made while the boiler is idle. 

Inspectors Will Give Special Instructions in Cases Not Covered 

by Tkese Rules. 
£3T If the Boiler shows distress or unusual behavior notify the Company at once. 

A Few General Suggestions for Operating Heating 
and Ventilating Apparatus in School Buildings. 

Furnaces. 

Care should be taken not to have too deep or heavy a fire in the 
furnaces during Spring and Fall, as there is great danger of over- 
heating the school-rooms. 

During cold winter weather run deep, full fires in the furnaces 
with coal up to within three inches of the top of the fire-pot at the 
edges, and well crowned above that level toward the middle. 



118 THE SCHOOL HOUSE. 

During extreme cold weather the grate-bars should be turned 
over at least twice each day. Ashes should not be allowed to 
accumulate in the ash-pits. 

Fresh-Air Windows. 

The fresh-air windows should be wide open daytimes in mild 
and calm weather, and never less than one-quarter open even in 
extreme weather, as judicious handling of the school-room vent- 
duct dampers should prevent the passage of too much cold air 
out of the building, thereby checking the inflow through the 
furnace chambers. 

Always close the fresh-air windows tightly nights, Sundays and 
vacations, but never close the fresh-air windows entirely when 
school is in session. 

Controlling Temperature of School-rooms . 

The temperature of the air entering each school-room should 
be regulated by the teacher occupying the room, — this is done 
by pulling the warm-air chain, or the cold-air chain, as the needs 
of the moment may demand. The teacher should pull the 
necessary chain but a little way at a time, — this to prevent too 
sudden a rise or drop in the temperature of the air entering the 
school-room. 

Dampers in Ventilating Dttcts. 

The outflow of air from each school-room is controlled by a 
damper, which should be adjusted by the janitor before each 
session of school, according to the outside conditions. In mild and 
calm weather, this damper should be wide open ; but when the 
weather is cold and windy, it should be partially closed. Never 
should it be closed entirely when school is in session. 

During extremely windy weather the vent-duct, unless controlled 
by the use of this damper, might take out from the school-rooms a 
larger quantity of air than the warm-air ducts could provide suffi- 
ciently heated, — the excess outflow finding its way into the school- 
room cold, through leakage around the windows and doors and 
through the walls. 

Intelligence should be used in operating these vent-duct dampers. 

Schoolroom Windows and Doors. 
A much better circulation of air within the school-rooms can be 
obtained if the windows and doors of the school-rooms be kept 
closed. Windows and doors should always be kept closed when 
the large furnaces are in operation. 



THE SCHOOL HOUSE. 119 

If, when the chains which allow the cool air to enter the school- 
rooms are pulled way down, the furnace drafts entirely checked, 
and it is still found that the school-rooms are uncomfortably warm, 
doors and windows may then be opened at discretion of the 
teacher. 

Air Rotation. 
At the close of school at night the fresh-air windows should be 
tightly closed and passage of air out from the building through the 
vent-ducts entirely checked ; the rotating dampers which allow air 
from the school-rooms to pass back to the furnaces should then be 
opened, and the furnace fires fixed for the night. A circulation of 
air within the building will thus be established, and a reasonable 
temperature maintained in the school-rooms during the night, with 
the minimum consumption of fuel. 

Stack- Heater . 

When the weather is cold enough to require good fires in the 
large furnaces which heat the school-rooms, these furnaces will 
often furnish enough power to move the air required ; but, on the 
other hand, when only low fires are needed in the large furnaces, 
it may be necessary to run the stack-heater in order to move the 
desired volume of air through the school-rooms. 

In warm or muggy weather, a good fire should always be kept 
in the stack-heater, not only for the ventilation of the school-rooms, 
but for the ventilation of the sanitaries as well. 

With Steam- Boiler Auxiliary . 

The steam boiler supplies steam for the radiators in the corridors 
and small rooms, and also furnishes heat for the vent-ducts. 

The steam may be supplied to the radiators in the corridors and 
small rooms when desired. 

In warm or muggy weather the vent-flue radiators should always 
be kept hot, in order to secure the proper ventilation of the 
school-rooms. 

Printed instructions (in large type) as above, if posted where 
they can be readily seen by the janitor, will be of great service 
to him when first taking charge of the heating and ventilating 
apparatus in a schoolhouse. 



CHAPTER IX. 



SANITARIES. 

THE sanitary appliances in schoolhouses should receive 
careful attention, not only when being installed, but 
also from the janitor. 

For buildings of large size the sanitary fixtures are generally 
placed in the basement, or, what would be better, in an extension 
in which they can be reached from the class-room floors and located 
where they can be properly ventilated, independently of the other 
parts of the building. 

On account of the cost of construction, and frequently from an 
architectural point, this is not often done, and part of the basement 
is utilized for that purpose. 

Where a suitable water supply is available and the fixtures are 
of good construction and properly placed and ventilated, the base- 
ment is not an objectionable place. 

Individual closets and fixtures are preferable to those known as 
range closets or latrines, but where the latter are properly flushed 
and vented they are not objectionable and are frequently used on 
account of the lower cost. With individual seat bowls those 
having a seat vent three or four inches diameter are to be preferred. 
The individual bowls should be vented into a pipe increasing in 
size as additional vents are connected and leading to a heated vent- 
flue or one where a fan is provided. 

In large and the best class of school buildings fans are used, but 
are more expensive than steam-heated flues. 

The partitions between the closets should be raised on metal 
supports from six to ten inches above the cement floor of the 
basement and no woodwork on or around the bowls should be 
used, except such as is required for the seats. This allows the 
janitor to use a hose freely and prevents the accumulation of offen- 
sive matter in places not easily reached. 

Each bowl should be provided with an automatic flushing device, 
of which there are several on the market that give good results. 
Apparatus is frequently used by which the whole number of bowls 
are automatically flushed at regular intervals. 



THE SCHOOL HOUSE. 121 

When range closets are used they should have a large vent and 
flush. It is better to have a separate vent for each seat and to 
unite the several vents into one main vent. 

Range closets should not be incased in wood on the sides or 
ends, and the full width between the partitions should be hinged in 
order that the whole length of the range can be thoroughly cleaned. 

The waste-pipe should be of ample size but not too large to 
prevent thorough flushing. 

For the main pipe six inches is a good size. Extra heavy iron 
pipe within the building is to be preferred to vitrified tile pipe, on 
account of the liability of tile pipe to become separated at the 
joints and allow leakage into the ground under the basement floor. 
The iron pipe should extend well beyond the foundation wall and 
in all cases should be well trapped and provided with suitable 
clean-outs. 

The writer has seen tile pipes that had been improperly connected 
or not made water-tight that had leaked so badly as to saturate the 
ground for a considerable distance, and where it has been found 
necessary to take up the floor and remove a considerable quantity 
of earth, replace it with fresh and substitute iron pipe. Where 
cremating closets have been used the saturation of the earth has 
been more noticeable than with water-flushed fixtures. 

Where there was no available water supply for flushing closets 
cremating closets have been used, and where the vaults were con- 
structed of brick laid in and covered with Portland cement and a 
good drain provided to remove the liquid matter, and where ample 
ventilation into a heated flue was provided, they have not been 
objectionable if properly cared for by the janitor. Odors were not 
perceived in the building, but complaints have been made by per- 
sons residing near the buildings when the closets were burned out. 

Where a water supply can be had it is better to use flushing 
closets. 

Where a water supply is available, but no system of sewers, 
flushing closets or range closets can be used by constructing a 
double cesspool; that is, two cesspools located at such a distance 
from the building that there is no danger of the leakage finding a 
way under the building — one cesspool to receive the waste-pipe 
from the sanitary fixtures and to allow the heavier and more solid 
matter to settle, the other to be constructed of brick or field stone 
to allow the liquid to filter off. 

The two cesspools are connected by a siphon pipe (six inches in 
diameter), which will, when the first receptacle has become partly 



122 THE SCHOOL HOUSE. 

filled with liquid, transfer it to the second or filtering cesspool. 
This arrangement cannot well be vised where the ground is con- 
stantly wet or where water in the ground is much above the bottom 
of the cesspool, or in clay. 

Each cesspool should be provided with a perforated manhole 
cover to prevent an accumulated gas from forcing its way through 
the trap and entering the schoolhouse basement. 

The urinals in a schoolhouse basement, where individual fixtures 
are not used, should be of slate, and should have suitable divisions 
for the older grades of pupils. In many school buildings the divisions 
are omitted on account of the additional cost of construction. 

A urinal has been constructed for an eight-room school building 
in accordance with the following specifications, and used with 
satisfactory results : 

"A gutter slab, 8 feet long and 18 inches wide and 3£ inches 
thick, in one piece ; one floor slab 8 feet long, 2 feet 6 inches wide 
and 1^ inches thick, sloped to the gutter slab; two end slabs 5 feet 
high, 2 feet 6 inches wide and 1 inch thick, and two back slabs 
each 4 feet long, 5 feet high and 1 inch thick, making the urinal 
when completed 8 feet long, 5 feet high and 3 feet 3f inches wide, 
including the floor slab. The gutter is to be countersunk 2^- inches 
deep at the outlet and 1 inch deep at the summit ; the back slants 
5 inches and is to be grooved f-inch into ends, and all are to be 
grooved ^-inch into the gutter slab ; all to be strongly clamped 
together and bolted to the brickwork, using brass clamps and brass 
expansion-bolts. The floor slab laps 3£ inches on the gutter and 
is closely fitted to the ends ; the outer or -waste-pipe is a brass 
cesspool, having 3-inch waste trapped. 

"A J-inch brass flush-pipe runs the entire length, placed within 
two inches of the top, and perforated so as to give a uniform and 
even flush; this will have a controlling valve. 

" The end slab near the outlet has an 8 by 10 inches opening to 
receive an 8 by 10 uptake vent-pipe and an 8 by 8-inch ventilating- 
hood which runs on top of the back slab the entire length. This 
connects with an 8 by 8-inch uptake vent-pipe, both of these 
uptake pipes and hood being made of heavy galvanized iron, 
properly secured in place. The uptake pipes are connected near 
the ceiling with the vent-duct leading to the heated brick vent-flue. 
All exposed parts of the slate are to be planed, rubbed smooth and 
well-oiled, the joints filled with slate cement in the best manner." 

A better arrangement is that of a slate urinal vented at the 
bottom of the front slab (having at least 12 square inches of 



THE SCHOOL HOUSE. 123 

opening for each 16 inches length) into a space between the front 
inclined slab and a perpendicular back slab, the space at the top to 
be at least four inches wide and the full length of the slabs and 
covered on the ends and top by slate slabs, except where it is 
vented near the center of the top by a galvanized-iron vent-pipe 
four inches wide and at least 20 inches long, which changes its form 
into a 10 inches diameter round pipe connected with a heated 
brick flue. 

The perpendicular back slab is grooved i-inch into the gutter 
slab. The inclined front slab at the bottom projects over the 
gutter at least three inches. 

The Boston Board of Schoolhouse Commissioners recommend, 
for water-closets and urinals, " Ventilation through fixtures, back 
of urinals, and 13 square inches local vent in water-closets. 

"Water-closets. The basement water-closets for primary and 
certain grammar schools are, approved washout vitreous earthen- 
ware or enamel iron latrines, or short hopper closets ; elsewhere a 
heavy wash-down closet, all as specified by the Commissioners, 
13 square inches local vent from each section of closet, automatic 
flush. 

"Slate partitions for latrines resting on top of range, 5 feet 
6 inches high and about 4 feet wide ; for closets 8 inches above 
floor, 5 feet 6 inches by 6 feet high and 4 feet wide; in both cases 
supported at ends with iron pipe from floor to ceiling. No doors. 
(These may be added later.) 

" Urinals. The urinals will be of slate, floor slab and trough, 
the back 4 feet 6 inches high, without partitions, flushed auto- 
matically with |-inch perforated pipe, vented at bottom (opening 
10 square inches for each 16 inches length) into space behind 
back. 

" Piping. Cast-iron must be in trenches in basement, running 
trap with direct indirect fresh-air inlets, clean-outs at every change 
of direction ; soils and vents exposed as far as possible, no 
asphaltum, but oil-tested red lead and three coats paint. 

"Supplies exposed as far as possible ; where covered may be lead, 
elsewhere brass, no nickel plated. Hot- water for janitor's use in 
basement, and, if convenient, for master's and teachers' toilets. 
Supply from boiler, and from summer boiler, if any, or from a 
gas-heater." 

All plumbing should be carefully tested to ascertain if it is tight 
and well trapped, especially where smaller pipes enter the main 
drain. ' 



124 THE SCHOOL HOUSE. 

Where water-closets are provided in teachers' toilet rooms they 
should be well vented. 

Soapstone sinks are frequently used in the basement in place of 
the ordinary cast-iron ones. Enameled iron is sometimes used. 

Many school buildings have stream drinking founts instead of 
faucets and dippers. 

Outside Saizitary Building's. 

The care of sanitary buildings in many towns and villages is a 
matter that is often neglected, and frequently they are found in a 
condition that does not bring credit to those who have the imme- 
diate care of such buildings. 

This is something to which school boards and teachers should 
give more attention than they usually do. They should see that 
such places are kept in at least a decent condition and that the 
vaults are properly cleaned. 

The janitor should be required to visit the sanitary building 
daily, cover the contents of the vault with fresh earth or ashes, and 
see that the seats, urinals and floors are in good condition. 

In winter especially these buildings are often found in bad condi- 
tion, as there is seldom any provision for heating. While- a stove 
in such buildings would add much to the comfort of the pupils, 
practically it would be of little use, as the fire would not be properly 
tended by the ordinary janitor, and some committees would object 
to.what they would call a needless waste of fuel. 

Where outside privies are used they should be placed at such a 
distance from the schoolhouse that odors will not reach the class- 
rooms when the wind is blowing from the direction of the sanitary 
building. When practicable they should not be located in a direc- 
tion from which the prevailing winds blow. 

Particular care should be taken that they are not located near the 
fresh-air supply for the furnaces or indirect radiators in the school 
building. 

When such buildings are used it is advisable to provide a tight 
vault with the walls laid in cement and covered on the inside and 
bottom with cement. 

A vault three or four feet deep and from four to five feet wide, 
extending the length of the building, will be found of ample size 
if cleaned out as often as it should be. 

The walls should be not less than 12 inches thick (some are 16), 
and the bottom of cement not less than two inches thick if the 
ground is solid, but if the building is placed where the ground is 



THE SCHOOL HOUSE. 125 

wet or not firm, there should be below the cement a layer of con- 
crete not less than four inches thick. 

The vault should extend beyond the rear of the building and be 
covered with inclined and hinged doors for removing the contents. 
On the rear of the building, and extending not less than two feet 
above the ridge, should be a ventilating shaft leading from the 
vault. 

The windows should be hinged and fitted with attachments for 
readily opening and closing. 

Locks should be placed on the doors for closing the building 
when the schoolhouse is not occupied. 

Where the ordinary trough urinal is used it should be well 
covered with sheet zinc and the floor under and at least three feet 
in front should be covered with sheet zinc and the joints made 
water-tight. 

Hinged self-closing covers should be furnished for the seats. 

Where it is not practicable to provide separate buildings for boys 
and girls, one with a partition may be used, and a board division 
fence or divided covered way leading from the schoolhouse to the 
building. 

Where the sanitary building is attached to the schoolhouse by a 
covered way (which is not always advisable), self-closing doors 
should be provided at each end and ample provision made for 
doors or louvres in the sides to prevent odors entering the school 
house. 

Brick piers are sometimes placed in the vault under the rear 
wall of the building if it is of considerable length. Three-inch 
iron pipe is preferable to the brick piers, as the vaults can be more 
readily cleaned when this is used. 

Whatever class of sanitary fixtures or buMdings are provided for 
schoolhouses it is requisite that constant supervision should be 
exercised by teachers and janitors to have them kept in good con- 
dition. It should be a teacher's duty to see that the janitor faith- 
fully attends to that part of his work. 

In many sanitary buildings, especially in the smaller towns, the 
writer has found conditions that should not be tolerated and would 
not have been allowed to exist if either the school committee or 
teachers had taken means to ascertain whether the janitor was 
attending to this part of his duty. 

Vaults were found that apparently had not been cleaned out for 
years, seats and floors covered with filth, obscene writing on the 
walls, and doors with hinges and fastenings broken. 



126 THE SCHOOL HOUSE. 

It has frequently been necessary to order seats and floors removed 
and new ones substituted in outside buildings, and in some cases 
new buildings were built. 

Such unsanitary conditions are demoralizing, and if parents had 
known of the existing conditions there would have been strong- 
protests entered with the school committee. 

Where a supply of fresh earth has not been obtained, kept dry 
and free from freezing, in cold weather sifted ashes from the 
furnaces or boilers can be used to good advantage in the vaults. 

In some badly-constructed cremating closets and in some of the 
so-called " foul air gathering rooms" with poorly cemented floors, 
trouble has been caused by the breaking, scaling or cracking of the 
cement, which allowed the liquid matter to soak into the ground 
under the basement floor and extensive repairs and alterations were 
required. Where any class of cremating closets are used in school- 
houses, extra care should be taken that the vaults are made per- 
fectly water-tight, thoroughly built and well drained. 

The heat in sanitary vent-shafts or ducts should be maintained 
at all times during the school term, except, perhaps, when there is 
a very considerable difference between the temperature in and out- 
side the building, or when a very strong wind is blowing across 
the top of the shaft and causing an outward flow of air. 

The sanitary vent-flue should never be placed in a position in 
which back drafts may be caused by the wind being deflected by 
roofs, towers or other projections. 

When a contagious disease appears among the pupils the entire 
schoolhouse should at once be thoroughly fumigated and disinfected 
under the direction of a competent person. 



PART II 



Plans and Descriptions 



OF 



School Houses 




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PLANS AND DESCRIPTIONS 

OF SCHOOL HOUSES. 



PLAX of a one-story, one-room schoolhouse with sections 
of heating and ventilating apparatus. The school-room 
is 28 by 32 feet and 12 feet high, with seats for 48 pupils. 
In front are two clothing rooms, one for boys and one for girls. 
A cast-iron sink is provided in each. There is a closet opening 
from the school-room for the teacher. Between the clothing-rooms 
are the furnace-room and fuel-bin. 

The heating is bv a medium-sized portable furnace. Fresh air 
is taken in through a galvanized-iron duct under the floor. This 
duct is 48 by 16 inches where it passes through the underpinning, 
and the bottom is slightly inclined toward the outside to allow rain 
that may be driven in to run out. The inlet is protected by a wire 
grill of one-eigbth-inch wire set in a channel-iron frame. 

A valve, with a pulley and a chain passing up into the furnace 
room, is provided, with a suitable catch to hold the valve in any 
desired position when a strong wind is blowing, or when the 
damper is closed at night. Before reaching the furnace the duct is 
tapped by a perpendicular one 24 by 30 inches, to furnish cold air 
for mixing with the warm air from the furnace when it is desired 
to reduce the temperature and yet supply fresh air to the 
school-room. 

A mixing-valve with pulleys and chain leading to the school- 
room is provided to enable the teacher to regulate the temperature. 
A suitable catch (as shown in another plate) is provided to hold 
the -chain and damper in any desired position. 

Warm air enters the school-room through an opening 30 by 30 
inches, covered with a wire grill of one-eighth inch wire, one-and- 
one-half-inch diamond mesh, set in a channel-iron frame. The 
bottom of this opening is eight feet above the floor. The warm 
air is thrown forward across the ceiling, spreading till it reaches 
the three outer or cold sides, where it is cooled and falls, and is 
drawn back across the lower part of the room and removed by the 
exhaust vent stack. 

Note. — The method of setting up this heating apparatus was designed by the writer 
and has given satisfactory results where used. 



130 THE SCHOOL HOUSE. 

In the top of the cold-air duct, before it reaches the upright part, 
is a trap-door covered on the bottom with galvanized iron which 
opens up into the furnace room. This is for rotating the air within 
the building at night or when the school-room is not occupied. 
By closing the outer damper in the fresh-air duct, closing the vent 
shaft opening from the school-room, and opening the doors between 
the school-room and furnace-room, the air is rotated through the 
furnace and a considerable saving of fuel is made. This trap-door 
should never be opened when the school-room is occupied. 

The exhaust vent or foul-air shaft has four-inch brick walls, and 
is 30 by 24 inches inside. Adjoining, and in the same stack, are 
the smoke flues for the furnace and vent-shaft heater. 

A small stove or " stack-heater," supported on two iron bars, is 
placed in the vent shaft just above the foul-air entrance. 

The foul-air vent opening is 24 by 30 inches, and the bottom is 
at the level of the floor, being covered with a wire grill similar to 
that at the warm-air inlet. 

A curved galvanized-iron damper is placed in the opening to 
regulate the outflow of air as may be desired on account of outside 
temperature or wind, or to close at night or when the school-room 
is not in use. , 

Plates Nos. II and III show plan and sections of what is 
known as the portable schoolhouse — a one-room school building 
for temporary use where the larger buildings are overcrowded, or 
for use until better accommodation can be provided. 

The building is constructed of light timbers and covered with 
matched and battened boards. The roof boards are covered with 
canvas, painted three coats. 

The building is supported on cedar posts and the space between 
the floor and the ground is inclosed with two thicknesses of matched 
boards, the outside boarding being perpendicular and the inside 
placed horizontally. 'The inside of the building is sheathed on the 
sides, ends and ceiling with matched boards. Between the upper 
and lower floor boards are two thicknesses of heavy building paper. 

The heating is by a jacketed stove or small portable furnace, 
which receives the air to be heated and for ventilation through a 
galvanized-iron duct leading from under the front platform, which 
is not boarded on the end, but provided with open lattice-work. 
A damper is provided in this fresh-air duct by which the quantity 
of air to be heated is regulated according to the temperature of the 

Note. — The method of setting up this heating apparatus was designed by the writer 
and has given good results. 



THE SCHOOL HOUSE. 



131 



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132 



THE SCHOOL HOUSE. 




THE SCHOOL HOUSE. 133 

I 

outside air or the force of the wind. This damper is operated bv 
a pulley and a chain passing up into the school-room. 

The air passes up between the casing and the stove and is intro- 
duced into the school-room through a curved top, which changes 
the direction of the current and throws the air across the ceiling to 
the coldest part of the room. This curved top is movable, and 
can be changed to throw the air against the direction of the prevail- 
ing wind when desirable, thereby securing a more even distribution 
of heat in the schoolroom. 

In the floor of the schoolroom and behind the jacketed stove is a 
trap-door opening into the fresh-air duct. By closing the outer 
damper in the fresh-air duct, opening the trap-door and closing the 
damper at the opening into the ventilating shaft, the air can be 
rotated through the building at night. This also enables the janitor 
to quickly warm the room in the morning before the school session 
begins. The trap-door should never be opened while the school is 
in session. 

The ventilation is by means of a galvanized-iron shaft in which 
is placed a small stove or " stack-heater" just above the top of the 
vent opening, the bottom of which opening is at the floor level. 

The stack-heater is supported on two iron bars and the lower 
part of the ventilating shaft from the floor to above the heater is 
provided with a double casing, filled with an non-heat-conducting 
material, preferably asbestos. This vent opening is covered by a 
detachable wire grill. 

At the vent opening is placed a curved galvanized-iron damper, 
operated by a chain and catch. 

The smoke from the jacketed stove and from the stack-heater 
enters a galvanized-iron smoke-pipe which passes up near the 
center of the vent-shaft and above a galvanized-iron hood or cap 
above the top of the shaft. 

The outer clothing of the pupils is to be hung on hooks in the 
porch clothing room, which is ventilated into the vent-shaft through 
a 10 by 12 inch register at the floor level, having valves. 

The vent-shaft is 24 bv 30 inches, inside measurement. The 
opening from the school-room is 30 inches long by 24 inches high. 

The galvanized-iron fresh-air duct is 36 by 16 inches, and the 
circular opening in the movable top above the jacketed stove is 
24 inches diameter. 

A small closet is provided for the teacher. 

Plates IV, V and VI. Basement, floor plan and plan and sections 
of heating and ventilating apparatus for a one-story two-room wooden 



134 



THE SCHOOL HOUSE. 




□ 



□ 



□ 



THE SCHOOL HOUSE. 



135 




136 



THE SCHOOL HOUSE. 



PLATE VI. 




SECTION THROUGH VENT SHAFT 



THE SCHOOL HOUSE. 137 

schoolhouse, intended to accommodate forty-eight pupils in each 
room. 

The rooms are 28 by 32 by 12 feet, lighted on two sides from 
the left and rear of the pupils. 

The teachers' platforms are omitted and a table-desk provided in 
each room. 

The pupils' outer garments are hung on racks in the corridor, in 
which is a well-trapped sink and a looking-glass. 

The basement is 9 feet 9 inches high, well lighted, the bottom 
concreted and covered with half an inch of Portland cement, and 
contains separate rooms for boys and girls, sanitary closets, coal- 
bins, cold-air room, furnaces and vent-shaft heaters. A well- 
trapped sink is also provided. 

If double run of sash or outside windows are provided for the 
class-rooms, especially if the building is in an exposed location, a 
considerable saving can be made in the amount of coal required. 

The school-rooms are heated by a large-size furnace encased in 
a double casing of galvanized iron set up inside a cold-air room, 
which is built of brick. If desired, an additional covering of non- 
heat-conducting material can be added to the outer casing of 
the furnace 

The fresh air is admitted to the cold-air room through two 
windows hinged and protected on the outside by a stout wire 
grating, and provided with cords and pulleys for regulating the 
amount of air admitted. 

A pit extends around and under the furnace, causing the air 
to be more evenly distributed than by the usual method of set- 
ting. The space between the two casings prevents the air being 
too rapidly cooled from the outside while and after passing the 
fire-pot. 

Over the top of the furnace are the mixing-valves for regulating 
the temperature of the air for the school-rooms. The cold air 
for mixing passes over the top casing of the furnace direct to the 
mixing-valves, each of which is operated from the school-room 
by pulleys, chain and catch. 

The warm-air ducts are 24 by 30 inches in cross-section. The 
warm air is admitted into each class-room through an opening 
30 by 30 inches, covered by a wire grill set in a channel-iron 
frame. The warm-air inlets are placed on the inner or warm side 
of the room, but near the outer or rear wall of the building, and 

Note. — The method of setting this furnace was designed by the writer and has given 
very satisfactory results where used. 



138 THE SCHOOL HOUSE. 

the bottom of the grill is eight feet above the floor. The temperature 
is regulated by the mixing-valves over the furnace. 

A four-inch diameter metallic thermometer with perforated back 
and sides, placed on the wire grill about two-thirds up from the 
bottom, half-way between the sides, will be of much service to the 
teacher in regulating the temperature. 

Two or three pieces of ribbon about one-quarter inch wide and 
about one foot long, tied into the grill just below the thermometer, 
will enable the teacher to judge of the amount and velocity of the 
incoming air. 

A thermometer, placed at about the level of the pupils' heads, 
when seated, and located on the partition in rear of the teacher's 
desk, should be provided ; also one for outside use, placed where 
the sun will not shine directly on it, for the janitor's use. 

The small supplementary heater for the corridor or hallway is 
intended for use in very cold or wet weather, also for drying the 
pupils' clothing and for a foot-warmer and drier. It also provides 
for moderately warming the basement. Each warm-air pipe from 
this heater is provided with a damper. This heater receives its 
air supply through a galvanized-iron duct and hinged window 
covered on the outside with stout wire-netting, and draws the air 
from under the front platform. In the stair risers in front and on 
each end of the outside front platform are wire-covered openings 
to admit fresh air to supply the heater. 

A register face, 27 by 38 inches, with a hinged door underneath, is 
provided in the floor of the closet between the two class-rooms, and 
opens into the cold-air room below for the purpose of rotating the air 
through the building at night or when the schools are not in session. 

The foul air from each school-room is taken from the floor level 
at the inner or warm corner of the room through a register face 
(without valves) 27 by 38 inches and a galvanized-iron duct down 
to the bottom of the foul-air shaft or stack, which it enters through 
an opening 24 inches high by 30 inches long. A valve or damper 
operated by a chain from the school-room is provided in each 
galvanized-iron foul-air duct. 

The brick foul-air shaft is 36 by 48 inches inside, and has a brick 
partition extending across the narrowest way to act as a cut-off and 
to prevent cross drafts from the ducts. This partition extends 
above the top of the foul-air entrances and on top of it is placed a 
cast-iron stove or "stack heater" with its smoke-pipe connected 
with a separate smoke flue. The fuel door and draft for the stack 
heater are tended from outside the shaft. 



THE SCHOOL HOUSE. 139 

A damper is provided in the smoke-pipe and operated by a rod 
extending through to the front of the shaft. A manhole door is 
provided under the stack heater and in the front of the shaft. 

The foul air from the corridor or hallway is taken out through 
a wire grill, 12 by 12 inches, under the sink and directly into the 
vent shaft ; a galvanized-iron deflector, hinged at the bottom and 
arranged to open or close by a chain and catch is placed at this 
opening. This vent opening is desirable for removing the foul air 
and odors from the clothing and preventing them from entering 
the school-room. 

The sanitary closets in the basement are of the individual, short 
hopper, automatic flushing pattern, having a four-inch diameter 
seat vent connecting with a duct (increasing in size as each closet 
is added) to the sanitary vent-flue, which is 16 by 48 inches, inside 
dimensions. 

The boys' urinal is of oiled slate, with perforated flushing pipe 
at the top and vented into the same vent-flue as the closets. 

An underground drain-pipe is provided for the closets and urinal, 
and connects with a sewer or a double leaching cesspool well in 
the rear of the building. 

No separate vent opening is provided for the basement, as it will 
be well ventilated through the sanitary fixtures and vent-shaft if 
the stack-heater which is placed in the sanitary vent-shaft is 
properly located and a fire maintained therein. 

Hose for washing out should be provided and the underground 
drain thoroughly trapped. 

If there is no available water supply for the sanitary fixtures they 
should be placed outside in a separate building and at a good 
distance from the school. 

A matched board removable porch on the front platform is an 
advantage in winter and will save fuel. 

Plates VII, VIII and IX show plans of basement, first and second 
stories, and a section through vent-shaft for a two-story two-room 
schoolhouse. 

This building belongs to a class of which many were built in 
Massachusetts some years ago and were practically without ventila- 
tion, except by means of windows and doors. They were often 
heated by wood-burning stoves. 

The heating and ventilation of such schoolhouses may be made 
satisfactory if constructed as shown herein. 

In the basement is located a large brick-set furnace with a brick 
cold-air room, connected with the outside air by a galvanized-iron 



140 



THE SCHOOL HOUSE. 




THE SCHOOL HOUSE. 



141 




142 



THE SCHOOL HOUSE. 




THE SCHOOL HOUSE. 143 

duct six feet wide by two feet deep. The duct enters at the top of 
the cold-air room and is provided with a damper and the outer 
opening is protected by a stout wire grill. 

Two galvanized-iron ducts, 24 by 36 inches, supply warm fresh 
air, one to each class-room. These ducts are provided with 
mixing-valves or dampers to regulate the temperature of the air for 
the school-rooms. 

The setting of the furnaee and arrangement of the warm-air 
ducts are as shown in plates VII, VIII and IX. In the floor of 
the first story is a cast-iron register without valves, but provided 
with a hinged door opening down into the cold-air room for rotating 
air within the building when the schools are not in session. 

The ventilation of the building is by a brick stack, inside of 
which are the smoke flues. The foul air from the lower school- 
room is taken down through a cast-iron register face, 27 by 38 
inches, in the floor and a galvanized-iron duct, which is gradually 
reduced in size to where it enters the bottom of the vent shaft, at 
which point it is 24 by 30 inches area. The register in the floor 
has no valves, but a damper operated by a chain and catch is 
provided. 

In the vent shaft, placed on iron bars just above the foul-air 
entrance, is a stove or "stack-heater" to raise the temperature of 
the outgoing air and produce a good outflow up through the vent 
shaft. 

The stack-heater should always receive its air for draft for the 
fire from outside the shaft. If the air for the combustion of the 
fuel in the stack-heater is taken from inside the stack, difficulty 
will be experienced in keeping the fire burning properly. The 
air rushing up on the outside of the heater will in a great measure 
destroy the draft for the fire. 

The foul air from the second story is taken directly into the vent 
shaft through an opening 30 inches long by 24 inches high, the 
bottom of which is at the floor level. 

A galvanized-iron curved damper is provided at this opening, 
and the opening is covered by a stout wire grill. 

The air brought down from the lower room and heated by the 
stack-heater passes up on the back of the curved damper and causes 
a good outflow of air from the second-story room. In each cloth- 
ing room is a 10 by 12-inch opening with a valved register and 
connecting with the vent shaft. 

Should it be desired to provide foot-warmers and heat the 
clothing rooms, it is advisable to use a small furnace (set up about 



144 



THE SCHOOL HOUSE. 



where the small coal-bin is located), which has pipes to the floor 
of each clothing-room. The supply of air for the small furnace 
should be taken from outside the building, preferably from under 
the front platform, which should have openings to freely admit air. 
A rotating register can also be used with the small furnace. 

When an attempt is made to heat the school-rooms and 
the clothing-rooms from the same furnace it is hardly ever suc- 
cessful. 

When the fresh-air supply for the large furnace is shut or partly 
shut off there will be a reversal of the air currents in the pipes to 
the lower clothing-rooms, and air will be taken down over the top 
of the furnace and be carried up into the school-rooms. 

Two standard size school-rooms are all that should be heated by 
a furnace, even if it is a large one. 



PLATE X. 




UU ' UI 4-i 



BA5CAENT 
FOUC liOQA 5CHOOL 



SMOWinO HUNTING ••• VENTILATION 



Plates X, XI, XII, XIII and XIV. — Plans and sections of the 
heating and ventilating apparatus for a two-story, four-room school- 
house, to be built of red brick with granite trimmings, slate roof, 
and copper gutters. 

In the basement, which is 10 feet 6 inches high and well lighted, 
are located the heating apparatus, fuel-room, cold-air room, 
sanitary fixtures and rooms for boys and girls, also bicycle racks. 



THE SCHOOL HOUSE. 



145 



PLATE XI. 



CLAbS PQOA 



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FOUB COOA SCHOOL 



146 



THE SCHOOL HOUSE. 





THE SCHOOL HOUSE. 147 

Bicycle runs are provided at each outside basement entrance. A 
well-trapped sink is placed in each basement room. 

The basement floor is of concrete and covered with Portland 
cement. 

On the first floor are two class-rooms 28 by 32 by 12 feet, 
intended to accommodate 49 pupils each, well lighted and the seats 
to be so arranged that the light will come from the left and rear of 
the pupils. There is also a small room for use of the teachers. 
Suitable closets are provided in each class-room and in the 
teachers' room. 

In the second story are two class-rooms similar to those in the 
first story, also a small room that can be used as a library or store- 
room, or as a superintendent's room. 

The corridors are 15 feet wide and well lighted ; clothing is hung 
on racks on the school-room side. 

The heating for the class-rooms is done by two large-size brick- 
set furnaces. The corridors and two small rooms are heated by 
a small sectional cast-iron boiler, which is also intended to furnish 
heat for the ventilating flues. Foot-warmers heated by the boiler 
are placed in the floor of the lower corridor, for use in cold or wet 
weather. 

A disc fan, operated by an electric motor, is provided for 
furnishing an abundant supply of fresh air in mild or moderately 
warm weather. In cold or windy weather the furnaces are to be 
used by the gravity system. 

If electricity is not available for running the fan it can be 
omitted, also the partition wall in which the fan is located. In 
such case the furnaces can be placed three feet nearer the rear 
wall. 

In cold weather, when it is desirable to quickly warm the class- 
rooms before the school session begins, the outside windows in the 
cold-air room and the dampers in the school-room and in the 
corridor vents being closed, the rotating register in the floor of the 
closet between the two lower class-rooms and all tbe doors in the 
class-rooms opened, the motor is started and the air is rotated 
through the building. 

If no fan is installed, the same arrangement of cold-air windows, 
dampers, rotating register and doors should be made and the air 
rotated by gravity. 

Before the school session commences or the pupils are admitted 
to the building, the vent-dampers should be opened, the rotating 
register and doors closed and the cold-air windows opened. Under 



148 THE SCHOOL HOUSE. 

no conditions should the rotation of air through the building be 
allowed while the schools are in session. 

When using the fan during school hours, two windows and the 
doors in the partition in the cold-air room should be closed, the air 
taken in through the middle window opposite the fan and driven 
through the fan-opening. When using the gravity system all three 
windows and the two doors in the partition should be opened. 

The fresh warm-air flues for the class-rooms are of brick, 
24 by 36 inches (area six square feet), and have mixing-valves or 
dampers, operated by chain, catch and pulley, by means of which 
the temperature of the incoming air can be properly regulated by 
the teachers without materially decreasing the volume. 

The vent-flues for the class-rooms are of brick, 24 by 30 inches 
(area five square feet) . The vent-flues, with the exception of the 
sanitary vents, have curved galvanized-iron dampers, operated by 
chain and catch. The sanitary vents should not be closed at 
any time. 

In each vent-flue, except the corridor vent, there are placed four 
sections, of five square feet each, of cast-iron radiators. These 
are placed just above the top of the inlet vent, spaced and inclined 
up and across the flue. In the corridor vent there are but two 
sections, or ten square feet of radiation. 

These radiators are connected with the small boiler and separately 
valved on each supply and return pipe. 

At night, or when the building is not occupied, the steam is 
shut off from the vent-flue radiators and the vent dampers closed. 

In extremely cold or windy weather it will not be necessary to 
keep steam on the vent-flue heaters, and in some cases of this kind 
the dampers can be partly closed, but in mild, calm or warm 
"weather steam should be kept on these heaters. 

The use of unsightly, costly and often worse than useless 
deflectors, diffusers and flap-valves is rendered unnecessary by 
properly locating the supply and vent-flues and having them of 
ample size and properly valved. 

The success of any system of heating and ventilation depends 
considerably on the good judgment of the janitor in operating the 
apparatus, and he should be carefully instructed in his duties. 

The teachers should also be instructed in the manner of operating 
the mixing- valves or dampers in the warm-air flues and the dampers 
in the vent-flues. 

Plates XV, XVI and XVII. — Plans for a two-story five-room 
school building- and for the heating and ventilation of the same. 



THE SCHOOL HOUSE. 



14!) 



The building is to be constructed of red brick with granite 
trimmings, slated roof and copper gutters. 

There are four class-rooms and one large assembly-room or hall, 
which can, if desired, be divided into two class-rooms; also two 



PLATE XV. 




•Five Cocn SCHOOL 

. BASEMENT' 

'"i^t 111 " -showing-heating- and-ventilation- 

5CALf OF FEET 

small rooms in the second story for the use of the teachers. In 
the basement, which has a concrete floor with a covering of 
Portland cement, are two sanitary rooms, cold-air rooms, boiler 
rooms and fuel rooms. 

The class-rooms are of standard size, 28 by 32 by 12 feet, 
intended to accommodate 49 pupils each. Transoms are over each 
door, except in the basement. The doors from the class and 
assembly-rooms open into the corridors, and each has a large 



150 



THE SCHOOL HOUSE. 



glass panel in the center to enable the teachers to see into the 
corridors. 

The corridors are 15 feet wide, with special racks on the walls 
for clothiner. 



PLATE XVI. 




SCAltOf PEET 



• FIVE COO/A SC HCBL- 
First story- 
showing-heating-and-ventflation 



The warm fresh air is admitted into the class-rooms through 
openings covered by wire grills 36 by 30 inches. The bottom of 
these openings is eight feet above the floor. In the assembly room 
the grills are 54 by 30 inches. The warm-air flues to the class- 
rooms are 36 by 24 inches (six square feet), and in the assembly 
room are 54 by 24 inches each. Each warm-air flue is provided 
with a galvanized-iron damper or mixing-valve to regulate the 



THE SCHOOL HOUSE. 



151 



temperature of the incoming air without materially decreasing the 
supply. 

The foul air is taken out at the floor level through wire grills, 
30 by 24 inches (five square feet) . In the assembly room the 
outlet grill is 72 by 24 inches (12 square feet). 

PLATE XVII. 




•FIVE COQM5CHQDL- 
• SECOND STOPY- 
•5HOWING-HEATING-AND-VENTILATIOM- 



Each foul-air outlet vent, except the sanitary vents, is provided 
with a galvanized-iron damper to regulate the outflow or shut it 
off when the building is not occupied. 

In each class-room vent-flue are placed four sections of cast- 
iron smooth-surface radiators, each having five square feet of 
radiating surface (a total of 20 square feet). In the assembly- 



152 THE SCHOOL HOUSE. 

room vent-flue are placed nine sections (45 square feet) of the 
same kind of radiators. These radiators are placed about one foot 
above the top of the vent opening from the room, evenly spaced, 
and inclined upward and across the flue. 

A vent -flue, 24 by 24 inches inside measurement, is provided for 
the corridors, both corridors venting into the same flue, and 15 
square feet of radiation is placed above the lower corridor vent 
opening. 

The sanitary vent-flues are each 20 by 24 inches and contain 15 
square feet of radiation. * 

The heating is by a horizontal tubular boiler, 54 inches in 
diameter, 15 feet 3 inches long, containing 60 three-inch tubes, 14 
feet long, and rated at 48 horse-power. 

A small sectional boiler is also provided for heating the vent- 
flues when the large boiler is not in use. 

The piping for the vent-flues is so connected that either the 
large or small boiler can be used as desired. Each vent-flue heater 
is separately valved, both on the supply and return pipes. 

The radiation for each class-room consists of 400 square feet of 
cast-iron indirect pin radiators, of 20 square feet per section, made 
into three stacks of 120, 140 and 140 square feet — one section, 
two sections or three sections to be used as may be required. Each 
section is to be separately piped and valved. 

The assembly-hall has two distinct groups of indirect radiation, 
480 square feet each, and each group is made up of four stacks, 
separately piped and valved. Around the outside walls are two 
lines of one-and-one-fourth-inch steam-pipe for use when the 
assembly-hall is not occupied. 

Two foot-warmers, each of 120 square feet, of the same kind of 
radiation used for the class-rooms, are provided in the lower 
corridor. 

Two lines of one-and-one-fourth-inch steam-pipe are also pro- 
vided in the corridors and placed under the clothing racks for 
drying the clothing in stormy weather. 

The sanitary rooms are heated by four lines of one-and-one- 
fourth-inch pipe, placed near the ceiling. 

Direct radiators are placed in the teachers' rooms and toilets. 

In the floor of a closet in each class-room is placed a register 
connecting with the cold-air room below. A tight-fitting shutter 
of galvanized iron is placed below the register to shut off the cold 
air from below when the register is not open. These registers, 
called rotating registers, are for rotating the air through the build- 



THE SCHOOL HOUSE. 



153 



ing when the schools are not in session. This is done as pre- 
viously stated in the description of a two-story four-room school 
building. 

The ventilation of the sanitary rooms and basement is through 
the fixtures, each closet having a four-inch diameter seat vent 

PLATE XVIII. 




' 'UU?11I 



5 ix Rocv\ school- 

"BASE/\ENT 

•SHOWING HEATING ^A / ENTILATlON• 



connected with a galvanized-iron duct leading from each line of 
closets and from the urinal to a steam-heated vent-flue. 

The air from the sanitary rooms being taken out through the 
closets and urinal vents prevents odors passing out from these 
rooms up into the building, as is sometimes the case when the 
room is vented by an outlet separate from that provided for the 
sanitary fixtures, or where air is forced into the sanitary room by a 
fan or gravity supply from the heating system. 



154 



THE SCHOOL HOUSE. 



A plenum condition should never be allowed in such rooms. 
An exhaust should be used instead of a plenum. 

Sufficient air will be supplied to keep the sanitary rooms free from 
odors, if taken into the sanitary rooms through a wire grill placed 
in the bottom of the doors leading from the basement corridor, and 
if the sanitary-vent flues are properly heated. 

PLATE XIX. 




l ijnf.niu ^1X BOCV\ SCHOOL ■ 

SCAtcormT F\R.ST 5TORY 

•SHOWING HF.ATINGS. VENTILATION- 



Plates XVIII, XIX and XX. — Plans for a six-room school 
building and for its heating and ventilation. 

The building is to be constructed of red brick with terra-cotta 
trimmings, slated roof and copper gutters. 

There are six class-rooms, each 28 by 32 by 12 feet and intended 
to accommodate 49 pupils. In the second story are two small 
rooms for the teachers' use. 



THE SCHOOL HOUSE. 



155 



The seats in four class-rooms are to be arranged to receive the 
light from the left and rear, and in two class-rooms the light is 
chiefly from the left. 

The corridors are 15 feet wide and contain the clothing- racks. 
Doors from the corridors to the class-rooms have each a large 
center panel of heavy glass, and transoms are provided over the doors. 

In the hasement are three rooms, a divided corridor, fuel and 
cold-air rooms. 

PLATE XX. 




51 v roo/v school- 

■Second Stody- 

.Showing Hfatinc & Vlntilation'- 



The fresh warm-air flues and the vent-flues for the class-rooms 
are of the same size and fitted with mixing-valves, dampers and 
steam radiation, as previouslv described for a four or five-room 
school-house, except that the sanitary vent-flues are 24 by 24 
inches area. 

Rotating" registers are also provided. 

There are two foot-warmers in the lower corridor. 



156 THE SCHOOL HOUSE. 

The general plan of the building is the same as that given for a 
five-room school, except that the assembly hall in the five-room 
building is replaced by two class-rooms, and the heating is by a 
combination of furnaces and steam heat. The six class-rooms are 
heated by three large brick-set furnaces, two rooms for each 
furnace. A cast-iron sectional boiler is provided for heating the 
corridors, vent-flues, foot-warmers and teachers' rooms. 

If desired, the boiler may be of sufficient size to warm the 
basement rooms by lines of one-and-one-fourth-inch steam-pipes 
placed near the ceiling. 

By the use of this boiler very satisfactory results are obtained, 
and the number of fires reduced from what •would be required if 
coal-burning stack-heaters and an additional furnace were used to 
heat the corridor and vent-flues. 

Plates XXI, XXII, XXIII, and XXIV. — Plans for a grammar 
school building. 

The building is to be constructed of light mottled brick with 
granite trimmings and slated roof, containing six class-rooms, one 
recitation-room, a manual -training room, two teachers' rooms, two 
sanitary rooms, boiler-room, coal-room and three cold-air rooms, 
besides the corridors and stairways. There are four class-rooms 
each 28 by 32 by 12 feet, two class-rooms 29 by 32 by 12 feet, 
each accommodating forty-nine pupils. The basement is twelve 
feet high, except the boiler-room and coal-room, which are two feet 
deeper, or fourteen feet in the clear. The basement entrances are 
built with a bicycle run to take bicycles down to the places provided 
for them. 

The corridors are fifteen feet wide, with walls of smooth water- 
struck brick -without "wood finish, being painted with light-colored 
gloss paint. Clothing is to be hung on special racks fastened to 
the walls, and there are two lines of 1^-inch steam-pipes below the 
racks and near the floor for drying and warming clothing in bad 
weather. Two foot-warmers are provided in the lower corridor. 
The heating is done by a two-pipe gravity return steam system. 

The two teachers' rooms are heated by direct radiators, the 
manual-training room in the basement by four lines of 1^-inch 
steam-pipe near the ceiling and also by indirect radiators. 

The boys' and girls' sanitary rooms are to be heated by four lines 
of 1^-inch steam-pipe near the ceiling, and ventilated through the 
sanitary fixtures, the seats having 4-inch diameter vents connecting 
with steam-heated vent-flues, with which the boys' urinal is also 
connected. Air is drawn into these rooms through wire grills in 



THE SCHOOL HOUSE. 



15' 




158 



THE SCHOOL HOUSE. 




THE SCHOOL HOUSE. 



159 



@ 



rn 



txi 



3— E^ 

o 


1 




5 J | 


{ 


ST 


ill J 


a 

n 

o 
< 

u 


1 ' 


1 



^ h 



160 



THE SCHOOL HOUSE. 




THE SCHOOL HOUSE. 161 

the bottom of the corridor doors, and the natural leakage around 
the windows and the removal of the foul air through the seat and 
urinal vents will properly ventilate these rooms and prevent odors 
from passing up and into the building. 

In the floor of the first story are three rotating registers for 
rotating the air through the indirect radiators when the schools are 
not in session. The air for the foot-warmers is rotated from the 
corridor at all times. A vent is provided in each corridor, both 
corridors being vented into the same shaft. Direct radiation is 
provided in each vestibule. 

The warm -air flues to the class-rooms are 24 by 36 inches in 
cross-section, and enter the rooms eight feet above the floor through 
openings covered by a wire grill 36 by 30 inches. Each warm-air 
flue is fitted with a mixing-valve or damper for regulating the tem- 
perature of the incoming air. 

An adjusting damper is also provided for each warm-air flue for 
regulating the amount of air for each room, as this will vary accord- 
ing to the height of the flue or its location with regard to the 
prevailing winds. 

Each vent-flue, except the sanitary, is to be provided with a 
galvanized-iron damper for regulating the outflow of air. 

In each class-room vent-flue there is twenty square feet of radiat- 
ing surface of lj-inch steam-pipe made into the form and placed 
as indicated in the section showing the vent-flues. 

The vent from the recitation room is carried down and through 
a galvanized-iron duct (No. 24 gauge iron) on the basement ceiling 
to the brick vent-flue for this room, which should have twenty-five 
square feet of steam-pipe radiation, placed about on a level with the 
floor of the first story. 

Each sanitary vent has twenty square feet of the same kind of 
radiation. 

The building is to be heated by two horizontal tubular boilers of 
27 horse-power each, and a cast-iron sectional boiler for heating 
the vent-flues when the larger boilers are not in use in moderately 
warm weather. These sectional boilers are generally designated 
" summer boilers." The boilers are to be so piped and valved that 
either or all of them can be used as desired. 

The recitation-room is to have 300, the two middle class- 
rooms 380, and the four corner class-rooms 400 square feet of 
cast-iron indirect radiation of twenty square feet per section, made 
into three sections for each stack, separately piped and valved, 
in order that the amount in use can be regulated according to the 



162 



THE SCHOOL HOUSE. 



weather. The vent-flue heaters are to be separately valved and 
piped. 

Hand bowls and faucets are provided in the first and second story 
corridors and cast-iron sinks in the boys' and girls' sanitary rooms, 
bowls and sanitary fixtures in the teachers' rooms in the second 
story. Mirrors are placed over the bowls and sinks for the pupils' 
use and in the teachers' toilets. 

Hose is to be provided for use in the basement. It is advisable 
to install a stand-pipe and hose in the basement and each corridor 
for use in case of fire. 

Sections are given showing the arrangement of the indirect radia- 
tors, mixing-valves and warm-air flues, the foul-air flues, heaters 
and dampers, adjusting dampers, rotating register and windows in 
the cold-air rooms, clothing racks and the catches for holding the 
chains for the mixing-damper and vent dampers. 

PLATE XXV. 




' ' 1 1 1 [ * i [ [ [ i . i -Basement- ■iShowikcWlatiwcsVentilatiok' 

■• 5 "" orrto ' -TIGHT RDM SCHOOL- 



THE SCHOOL HOUSE. 



163 



Plates XXV, XXVI, XXVII and XXVIII.— Plans for a two- 
story, eight-room, brick school building, showing the heating, 
ventilating and sanitary appliances. 

A combination of the gravity and mechanical systems of heating 
and ventilation is used. 

In the gravity system there are 400 square feet of indirect cast- 
iron heating surface for each school-room. This is divided into 
stacks of 100, 140 and 160 square feet for each class-room, separ- 
ately piped and valved, in order that either a part or the whole can 
be used as desired, and is sufficient to meet the requirements of 
heating and ventilation in the coldest weather that occurs in 
Massachusetts. 

Fresh air is admitted through the windows in the two cold-air 
rooms in the basement, when the gravity system is in use (the ducts 

PLATE XXVI. 



CLAtoRCJiH 





r-j ;;,';,, ;-i. 

•JLALC OPFCCT 



rpRiT 3TORY- •3H0W]NCrltAT!NG'«» , /£NTILATMK' 



164 



THE SCHOOL HOUSE. 



leading from the fan being then closed) in cold weather, when the 
difference between the inside and outside temperature is sufficient 
to furnish a full supply of warm, pure air by gravity flow. 

In the floor of the closet between the rooms on each side of the 
lower corridor there is a rotating register connecting with the cold- 
air rooms below. 

PLATE XXVII 




-oecohd story - 
--Eicht Room School- 



-Showing Meating ••.Ventilation ■■ 



In the basement of one of the corridor extensions there is also a 
supplementary means of supplying air by a fan driven by an electric 
motor, and 800 square feet of indirect cast-iron radiation, divided 
into sections of 100, 140 and 160 square feet, as in the other cold- 
air rooms. 

This part of the apparatus is intended to be used in moderate 
and calm weather, when the requisite supply of fresh air is not 
easily obtained by the gravity system without overheating, espe- 
cially in the spring and fall months. 






THE SCHOOL HOUSE. 



165 



When in use the windows leading from outside directly into the 
gravity cold-air rooms are to he closed, and the sliding damper at 
the entrance of the galvanized-iron ducts into the gravity cold-air 
rooms opened, the windows in the cold-air corridor extension base- 
ment opened and the fan run by the motor, the air either passing 
through the heated radiators, or, by means of a specially designed 
damper, going to the fan without passing the radiators. This 

PLATE XXVIII. 




OcctionThbouch E.B--I -.DEJAIl>rOR-HD\TlNC»YENTlWnNG--aCT!™--mRfWTH-c-C- 

■E!GHT-R f 5)M-3CHOOL- 



damper can be used as a mixing damper to regulate the heat and allow 
more or less warm or cold air to pass the fan as may be desired. 

A four-inch diameter metallic thermometer, placed in the side 
of the galvanized-iron duct leading to the air rooms at the bottom 
of the warm-air flues, which go to the schoolrooms, will enable 
the janitor to regulate the temperature of the air sent from the fan. 
Should it be desired to use the fan when the air is colder than the 
fan radiation can properly warm, a portion of the radiation in the 
other cold-air rooms can be used to good advantage. 

By the use of this combination system forty cubic feet of air per 
minute can be supplied for each pupil under all conditions of 
temperature. 



166 



THE SCHOOL HOUSE. 



While it may add somewhat to the first cost of the building, 
the effective work will more than make up for the extra first 
cost. 

If electric power is not available, the fan may be run by an 
engine having a large diameter, low-pressure cylinder. This, how- 
ever, will require a change in the piping and setting up of this part 
of the apparatus, and a small boiler of sufficient size to run the 

PLATE XXIX. 



., \V„ ,11 V ' 

« v n A\ "i . xU > 

„«■* - ''''III'' '•' 

iJ'^UrtWl iiiimf 'I'm .<iiqii. 



f%>; 




BROCK AVE., 5CHO0er; 

NEW BEDFORD MASS.,U.SA. 



engine and also furnish (at a reduced pressure) steam for the vent- 
flue heaters when the larger boilers are not in use. 

In addition to the two horizontal tubular, a cast-iron sectional 
boiler is supplied for heating the vent -flues when the electric motor 
is used or when the larger boilers are not fired up. 

The warm-air flues and the vent-flues are of the same size and 
location, and similarly provided with dampers and heat, as pre- 
viously described for other school buildings. 

Sections are given showing cold-air rooms, indirect radiators, 
mixing-dampers and fan. 

Plates XXIX, XXX, XXXI and XXXII. — Perspective and 
plans for an eight-room schoolhouse. 



THE SCHOOL HOUSE. 



1G7 



This schoolhouse is in the city of New Bedford, C. Hammond 
and Sons being the architects, and is a two-story building con- 
structed of red brick with granite trimmings; the roof covered 
with black slate. 

It contains eight class-rooms and two teachers' rooms, also wide 
corridors and vestibules. In the basement are located play rooms 
and sanitary rooms for the pupils, a room for the janitor, boiler 

PLATE XXX. 




'BASEMENT PLAN 



BROCK AVE., SCHOOL. 

NEW BEDFORD, MASS..U.5 -f 



and fuel rooms, together with fresh-air chambers and the indirect 
steam-heating radiators and boilers. 

The class-rooms are intended to accommodate 49 pupils and 
teacher, a total of 50. They are well lighted, the pupils' seats ami 
desks being so placed that the light is received from the left and rear. 

The blackboards are of best black slate. 

The teachers' rooms in the second story are provided with heat- 
ing radiators and toilet closets. 

The corridors are wide and well lighted, there being glass in the 
transoms over the doors and a large panel of heavy glass in each 
door leading from the class-rooms. 



168 



THE SCHOOL HOUSE. 



The walls of the corridors, staircase wings and vestibules are 
faced with selected smooth-cut brick. The vestibule floors are 
of tiles. 

The basement floor is of concrete, well rolled and smooth. The 
plastering is of Windsor cement, and steel lathing is used on ceil- 
ings and wooden partitions. The plastering on the brick walls is 
laid directly on the brick. 

PLATE XXXI. 




floor plan BROCK AVE..SCHOOL, 

F.RST FLOOR PLAN. NEW BEO p ORD#MASS . tU . s . A . 



The partitions around the stairways are provided with fire stops, 
as required by the Massachusetts building regulations. 

The conductors, gutters and flashings are of rolled copper. The 
inside finish of the first and second stories is of selected red oak, 
and the floors double, the upper floors being of the best rift yellow 
pine, not over three inches wide. 

In each corridor are clothes rails with bronzed hooks for holding 
the pupils' clothing. 

Electric call-bells and speaking-tubes are provided from each 
class-room to the principal's room, also to the janitor's room, and 
from the main entrance to the janitor's room. 



THE SCHOOL HOUSE. 



1 69 



The sanitary closets and urinals in the basement arc provided 
with automatic flushing tanks, a'nd arc well trapped and well 
ventilated into a special vent-flue which contains steam-pipes, to 
cause an outflow of foul air from the basement rooms and sanitary 
fixtures. 

In the first and second story is a galvanized-iron stand-pipe and 
50 feet of hose for use in case of fire. Suitable hose racks are 
provided. 

PLATE XXXII. 




SECOND FLOOR plan. BROCK AVE SCHOOL, 

NEW BEDFORD. MASS.,U.SlA. 



In the basement, corridors and teachers' rooms are water faucets 
and hasins or howls well trapped. 

Two horizontal tubular boilers are provided for heating the 
building, each being 42 inches in diameter, 14 feet long, having 
38 tubes three inches in diameter and 13 feet long. Each boiler is 
rated at 32 horse-power and tested to 150 pounds under hydraulic 
pressure. 

Safety-valves, automatic damper-regulator, steam-gauges, water- 
gauges, fusible plugs, blow-off cocks and all required valves are 
provided. 



170 THE SCHOOL HOUSE. 

A supplementary sectional boiler of the rated capacity of 400 
square feet is also provided for the vent-shaft heaters and for use 
in mild weather in the place of the main heating boilers. 

The piping for the vent-shaft heaters is so arranged that either 
or both main boilers or the sectional boiler may be used as desired. 
The piping in the building is what is known as the two-pipe 
system, with supply and return for each radiator or coil, and so 
adjusted that water-hammer or snapping is prevented during the 
circulation of the steam, and suitable allowance is made for expan- 
sion and contraction. The return pipes are not shown on the 
drawings, but generally follow the line of the supply pipes. 

Valves are provided by which part or the whole of the heating 
radiators may be used as desired. The fresh air for each class- 
room is warmed by being passed through cast-iron indirect 
radiators in the basement. Four hundred square feet of indirect 
radiation is provided for each class-room, and is divided into three 
sections or stacks, so that a part or the whole may be used as 
desired. 

In the teachers' rooms and corridors are direct radiators, and in 
the basement are lines of steam-pipes overhead. Radiators are 
also provided for bringing warm air up through two registers in 
the floor of the first-story corridor, the air being rotated from the 
corridor floor near the stairway extensions. These are designated 
as foot-warmers, and enable the pupils to warm their feet and hands 
and dry their clothing in cold, stormy weather. 

In the floor of the closets between the class-rooms in the first 
story are what are termed rotating registers, for use at night or 
when the rooms are not in use. The windows in the cold-air 
rooms and the dampers in the vent -flues being closed, the rotating 
registers are opened and air is drawn down from the class-rooms, 
passes through the indirect radiators and is returned to the class- 
rooms through the warm-air flues, thereby keeping the rooms warm 
and saving fuel. 

The warm fresh air is brought into the class-rooms through 
openings eight feet above the floor as shown in the drawings, and 
the vitiated air is removed through openings at the floor level, 
located as shown in the plans. The warm-air and foul-air flues are 
of brick, and well smoothed up on the inside. 

Each foul-air flue contains 20 square feet of steam-pipe heating 
surface for causing an outward flow of vitiated air, and is also 
provided with a curved damper of galvanized iron, operated by a 
chain and catch, by which the amount of air taken from the rooms 



THE SCHOOL HOUSE. 171 

can be regulated or shut off when the rooms are not in use. In 
each warm-air flue is a galvanized-iron mixing-valve. 

There is also an adjusting damper by which the supply of fresh 
warm air to each room may he regulated or shut off if any room is 
not occupied. 

The direct radiation consists of vertical loop cast-iron radiators 
of an aggregate of 325 square feet of surface in corridors and 
teachers' rooms, and 280 square feet of surface of 1J inch steam- 
pipe in coils overhead, in the hasement. 

The indirect radiators for the foot-warmers consist of 100 square 
feet each of cast-iron radiators. 

At an inspection of this building the following conditions were 
found : 

Weather, fair ; wind north and moderate ; outside temperature, 
21° F. ; outside relative humidity, 57 per cent; harometer, 30.32; 
average temperature of air at inlets to class-rooms, 87.1° F. ; average 
supply of fresh air through inlet to each class-room, in cuhic feet 
per minute, 2,337; average amount of air removed at outlet from 
each class-room, in cubic feet per minute, 2,984; average amount 
of air, in cubic feet per minute, supplied at inlet for seating 
capacity of each class-room, 47.7; average amount of air, in cubic 
feet per minute, removed through outlet in class-rooms, for each 
pupil, 60.9 ; greatest amount of air, in cubic feet per minute, 
supplied at inlet to any class-room, 3,247; least amount, 1,730 
cubic feet; average difference in temperature in any room, taken at 
the same time at four places, at the breathing plane, 2° F. ; least 
difference at same points, .5° F. ; average temperature at teachers' 
desks, 69.5° F. Xo uncomfortable drafts could be perceived in 
the several rooms. 

Plates XXXIII, XXXIV and XXXV.— Plans for a small high or 
a grammar school — a two-story building constructed of yellow 
brick, with vellow terra-cotta trimmings and slated roof. If used 
as a grammar school the rooms intended for the chemical and 
physical laboratories can be used as class-rooms. 

In the first storv are four class, two recitation, and two teachers' 
rooms, with toilets connected. 

The corner rooms are 28 by 32 feet and 12 feet high, intended 
for forty-nine pupils. The recitation rooms are each 17 feet 
8 inches by 28 feet. 

The teachers' rooms, including toilets, are each 11 feet 4 inches 
by 28 feet. The center corridor is 15 feet and the front corridor 
12 feet wide. 



172 



THE SCHOOL HOUSE. 




THE SCHOOL HOUSE. 



173 




174 



THE SCHOOL HOUSE. 




THE SCHOOL HOUSE. 175 

In the second story are two class-rooms, a chemical and a physi- 
cal laboratory, each 28 by 32 feet by 12 feet high, an assembly 
hall 36 by 73 feet, and two storage-rooms in the stairway exten- 
sion. The stairways at each end of the building are six feet wide 
and railed on both sides. The main doors open both ways, as do 
also the assembly-room doors. 

In the basement, which is 12 feet high, except the boiler-room, 
which is 14 feet 6 inches in height, is a manual-training room, 
a boys' and a girls' recreation-room, sanitary rooms, boiler-room and 
coal-room, cold-air rooms and places for bicycles. Two stairways 
lead up to the first story and there are two doors from the outside 
to the stairway extension. 

The basement floor is of concrete, with a covering of Portland 
cement or rock asphalt. 

The interior walls and partitions are of brick, except between 
the tw r o recitation-rooms, on the corridor sides of the teachers' 
rooms, and the small storage -rooms in the second story. Between 
the rooms are closets with doors connecting with the class-rooms. 
All wooden partitions are lathed with expanded metal lathing, 
which is the only kind of lathing used throughout the building. 
Fire stops, which are required by the Massachusetts building laws 
in all school buildings, are also built. 

The walls of the corridors and stairway extensions have a face 
of good quality smooth brick, well laid and painted with light 
colored gloss paint but with no wood finish. 

Bookcases with glass doors are placed in each class-room between 
the heat and the vent -flues. 

The windows in the first and second story rooms have a double 
run of sash; the basement, stairway extension and corridor win- 
dows, single. The windows between the corridors and rooms are 
six feet aboye the floor, and each door, except to the store-rooms and 
teachers' rooms, has a center panel of heavy glass. There are 
windows over the doors leading to the front and end entrances. 
All inside'doors have glass transoms. 

The corridors in which clothing is to be hung have wooden 
hanging frames projecting one foot from the sides, with two pieces 
for hooks, the lower one nearest the wall and the upper one project- 
ing, with hooks alternating, to prevent the crowding of the clothing. 

In the basement of the stairway extensions are stands for bicycles, 
which are to be brought down a runway by the side of the base- 
ment steps. Gymnastic appliances are supplied in both boys' and 
girls' recreation rooms. 



176 THE SCHOOL HOUSE. 

The manual-training room is fitted with lathes, grindstone, 
work-benches and tools. 

The chemical laboratory has tables, sinks, chemical closets with 
glass sliding doors, water, illuminating gas, electric power and the 
requisite apparatus. The physical laboratory is also supplied with 
the necessary tables and apparatus. 

The assembly hall has two large ceiling lights, connecting with 
skylights in the roof. The ceiling lights are fitted with roller-shade 
curtains. One of the ceiling lights and one skylight has a hinged 
section operated by chains and pulleys, which can be used for ven- 
tilation should the room become overheated in moderate weather. 

The building is heated by a low-pressure, two-pipe, gravity, 
steam system, with two horizontal tubular boilers, each 54 inches 
in diameter, 15 feet 3 inches long, containing 60 three-inch tubes 
14 feet long; also by a smaller horizontal tubular boiler, 36 inches 
in diameter, 9 feet 3 inches long, containing 34 two-and-one-half- 
inch tubes, 8 feet long. This small boiler is intended to furnish 
steam for the steam-pipes in the vent-ducts and for a low-pressure 
engine to run the turning lathes, etc., in the manual-training room 
when the large boilers are not in use. It can also be used to warm 
the radiators in the spring and fall months, when but very little 
heat is required for a part of the day. The three boilers are set, 
piped, valved and connected so that either may be used as desired. 
When it is necessarv to use very low pressure in the larger boilers for 
warming the building in moderate weather, the small boiler can be 
used at higher pressure to run the engine for operating the lathes and 
also for heating the vent -fl vies. A reducing pressure-valve should 
be provided, also a separator, tank, pump, and pump governor. 

If an electric motor is used for running the lathes, it will not be 
necessary to use the pump, etc., the small boiler can be reduced 
in size and the system can be run by gravity return. This would 
be advisable where electric power is to be had. 

By having the boiler-room lower than the other parts of the 
basement a good return of water by gravity to the boiler is secured, 
and a complicated system of traps, pumps, etc., is rendered 
unnecessary. The supply and return pipes are of ample size, 
properly pitched, graded, dripped and valved, so as to secure a free 
and noiseless circulation and return to the boilers. 

The class-rooms, assembly hall, recitation rooms, laboratories 
and teachers' rooms are heated by stacks of indirect radiators of 
the H. B. Smith School Pin, Bundy Newport, American Sterling, 
or similar pattern, placed in the cold-air rooms in the basement ; 



THE SCHOOL HOUSE. 177 

each stack being divided into three sections so that part or the 
whole may he used as desired. 

Direct radiation is supplied in the corridor and stair extensions, 
and two lines of onc-and-one-quarter inch steam-pipe under the 
clothing racks in the corridors for drying in storm} weather and 
tor heating in extremely cold weather. 

At each end of the lower corridor there are floor registers without 
valves for use as foot-warmers, the air being drawn down through 
the register nearest the door, passing through the stack of radiators, 
which are to be cased with galvanized iron and suspended from 
the basement ceiling, and coming -up through the register farthest 
from the door. Good exhaust Hues are provided from the corridors, 
and the leakage of air into the corridors is sufficient to keep them 
in good condition. 

in the chemical and physical laboratories four lines of one-and- 
one-quarter-inch steam-pipe should be placed on the two exposed 
sides, to be used at night to prevent freezing in extremely cold 
weather when the rooms are not in use. 

Direct radiation is placed in the assembly hall in addition to the 
indirect, to keep the room partly warmed and to heat quickly when 
the indirect is turned on before the room is occupied. When 
occupied the direct should be shut off and only the indirect used. 

The manual-training room in the basement is also supplied with 
direct and indirect radiation. The recreation rooms and sanitary 
rooms are warmed by lines of overhead steam-pipes, the supply 
mains in the basement being protected by non-heat-conducting pipe 
covering. 

The ceiling of the boiler-room and the cold-air rooms are 
specially protected by non-heat-conducting material placed between 
the flooring and the metallic lathing — in the case of the boiler- 
room, to prevent the heat passing up through the floor and over- 
heating the rooms above, which often happens when the boilers 
are located under the school-room and no protection is provided 
other than the wooden floors. It is advisable to construct the ceil- 
ing of iron beams and terra-cotta arches and make the boiler-room 
fire-proof. 

If the cold-air rooms are not protected overhead the cold air 
chills the floor directly over them, sometimes to an uncomfortable 
degree in extremely cold weather. The cold-air room windows 
should be hung in two parts and be provided with cords and pulleys 
for opening and closing. 



178 THE SCHOOL HOUSE. 

The fresh warm air is taken into the rooms through inlets of the 
same size and location as previously described in other plans. 

The dimensions of each of the four warm-air flues for the 
assembly hall are 52 by 24 inches. 

Tests of the best work show that by having the warm-air flues 
of liberal size the air is introduced into the rooms at a lower velocity 
and temperature than when the flues are too small. In moderate 
weather this is a decided advantage, as a sufficient amount of fresh 
air can be supplied without overheating the room, as was the case 
in some of the earlier work, where the temperature had to be raised 
too high for comfort in order to obtain the required volume of air 
with small ducts. 

In some cases, especially where fans or blowers have been used, 
the ducts have been reduced in size under pretense of cheapening 
the cost of construction, and the air forced into the room at a high 
velocity, causing uncomfortable drafts and a needless expenditure 
of power. 

Wire grills are used instead of cast-iron registers to cover the 
inlets and outlets. Mixing valves are supplied for warm-air flues. 
Adjustable galvanized-iron cut-offs or adjusting dampers are pro- 
vided at the bottom entrance for the warm air to regulate the supply 
of air to the several rooms under the varying conditions of wind and 
temperature or to cut off the supply from any unoccupied room . 

The use of double windows will be of great service in very cold 
and windy weather, and will to a considerable extent prevent too 
rapid cooling and precipitation of the air by the glass surface 
which often causes downward drafts in front of single windows. 
A considerable saving of fuel can be made by using double 
windows. 

The openings from the rooms and corridors into the vent -flues 
are of the size and location previously described in other plans. 
Galvanized-iron dampers are also provided for these vent openings. 
Vent-flue heaters are installed. 

By the use of steam-pipes or radiators in the vent -flues a good 
velocity is given to the outgoing foul air, back draft is prevented 
without the use of flap-valves, whose chief purpose appears to be 
to obstruct the outflow of the foul air and to cause a disagreeable 
noise by flapping up and down when moved by the wind. 

Experience and not theory has taught that means should always 
be provided for causing an outflow of the foul air through the vent- 
flues and ducts, either by heat or mechanical means. Attempts to 
cause an outflow by other methods, especially when the outlets are 



THE SCHOOL HOUSE. 179 

obstructed by worse than useless flexible valves, which are liable 
to close when the room is occupied and ventilation required, and to 

open when the room is unoccupied and no ventilation needed, 
usually result in noticeable failures, as proved by numerous tests. 

With these contrivances there appears to be no practicable way 
of adjusting the outflow, and in extremely cold and windy weather, 
when the outflow will need checking, the flap-valves will be open 
to their full capacity ; but in mild and calm weather, when they 
should be wide open, they are liable to be closed. 

The sanitary closets are of a pattern having an especially large 
local vent (four inches in diameter) and each closet is vented into 
an underground duct running to the smoke-flue surrounding the 
iron smoke-pipe from the boilers. 

Each closet has an automatic flush. The divisions or par- 
titions between the closets are raised eight inches above the floor 
on metal standards, which allows the janitor to use w'ater liber- 
ally for washing the floor through a hose furnished for that 
purpose. 

Each line of closets is connected with a well -vented and trapped 
soil-pipe. 

The urinals are fitted with a perforated flushing-pipe, and have 
a liberal vent connected with the main closet vent-duct. The 
discharge pipe should be well trapped and vented. 

The sanitary -rooms are ventilated through the closets and urinals 
to the space around the boiler smoke-pipe. 

All plumbing should be of the open or exposed pattern and all 
fixtures w T ell trapped and vented. 

Plates XXXVIII and XXXIX are designs by the late John T. 
White, the friend and companion inspector of the writer for 
eighteen years. 

Plate XXXVIII. — Design for a direct -indirect radiator. 

This radiator is designed to be used in small halls or in churches, 
where it may be easy to provide for a strong exhaust leg of a venti- 
lating system, but difficult to arrange for a straight indirect method 
of heating and supplying air. 

Almost any good direct radiator may be used or a coil of pipe. 

The radiator is first cased in metal, and may then be finished in 
wood in any way desired. 

The fresh-air opening has an area of two square inches for each 
square foot of radiation; but the supply of air from outside may be 
controlled by damper, as shown, which can be held in any position. 
The inside damper is always to be entirely open or shut. When 



180 



THE SCHOOL HOUSE. 




1DWU 



aavog 



THE SCHOOL HOUSE. 



181 



open, the air is taken from the room, and the effect is, of course, 
nearly the same as with a direct radiator. 

Such a radiator with 100 square feet of surface has been found 
to furnish 500 cubic feet of air per minute under fairly favorable 
conditions. 

PLATE XXXVII. 




SANITARY BUILDING 



The fresh-air opening, extending nearly the entire length of the 
stack, gives a more even distribution of air to the heating surface 
than (as is generally the case) where the opening is near the center 
of the stack and the area is obtained by one which is high and short 
instead of low and long, as shown in this design. 



182 



THE SCHOOL HOUSE. 



PLATE XXXVIII. 





Dan per Controller 

• No Scale • 
top of Floor. \ 



Section 




•Pla n 



5c ALE 

1 1 I 1 1 I I I I I I I I 

One Foot 



■Design for Direct-Indirect Radiator. 



THE SCHOOL HOUSE. 



183 



Plate XXXIX. — Design for setting a portable furnace, showing 
a method of setting a portable furnace in a small hall or in a 
church, where the registers are necessarily placed in the floor. 



PLATE XXXIX. 



ROTATING 
REGISTER 




REGISTER 



feffiW ^v' 



mrnn 




FURNACE - SHOWING MIXING VALVF. 



REGISTER 
OVER 



In such cases, when the room is too warm, the usual remedy is 
to close the register and thus shut off the supply of air, throwing 
all the heat back on the furnace, increasing the danger from fire 
and possible injury to the pipes and castings. The registers here 
shown have no valves, and the temperature of the incoming air is 
regulated by a mixing-valve in each duct as shown. 



184 



THE SCHOOL HOUSE. 



There is a damper for controlling the supply of outside air, and 
a rotating damper is provided. 

The cold-air and warm-air ducts are much larger than those 
generally installed. 

There is a pit under the furnace about two feet deep — -an 
essential feature for good work. 

If any small rooms are to be heated, branches can be taken from 
the large pipes with switch dampers to control the flow of air. 

PLATE XL. 




CORRIDOR FOOT-WARMER 



Plate XL. — Foot-warmers to be placed in schoolhouse corridors. 

Six sections of indirect cast-iron pin radiators are made into a 
stack containing 120 square feet of radiating surface, which is 
suspended below the basement ceiling on two 1-J-inch iron pipes, 
which are secured to the floor timbers above by iron hangers. 
The sections are 15£ inches high at their highest part and 
36 inches long. 

The pins are one inch long and the sections are set up four inches 
on centers with one-half inch space between the ends of the pins. 

Two-inch right-and-left nipples are used for connecting the 
sections, which are tapped for two-inch supply and return. A 
f-inch air-valve is placed in the quarter-turn or elbow of the 
return. This air-valve is placed in a position, where, should it be 
desirable to moisten the air, a small quantity of steam may be 
allowed to escape through the air-valve. 



THE SCHOOL HOUSE. 185 

The casing is of twenty-four gauge galvanized iron put together 
with screws, nuts and angle iron, so that it may he easily removed 
should it he required to make repairs on the heating-stack. In the 
hottom of the casing are two clean-out slides for removing any 
dirt or substance that may fall through the register gratings in the 
floor of the corridor. 

The air is taken from the corridor down on one side, passes 
under and up through the radiator-stack and ascends to the corridor 
through another register in the corridor floor. 

This arrangement prevents the accumulation of dirt and various 
substances that would fall on the heated radiators through a register 
placed directly above the heating stack. 

Covering Boilers. 

Covering boilers by the use of sand is not advisable, because if 
cracks appear in the setting, the sand will deposit in the cracks 
when the wall is heated and will continue to doso and widen the 
cracks. 

When a boiler is arched over with bricks, care should be taken 
that the arch does not rest on the boiler, and that at least an inch 
space is left between the boiler and the brick arch, which should 
be self-supporting. 

An eightv-five per cent magnesia covering when properly applied 
makes a very desirable non-heat-conducting protection over the 
boiler and gives very satisfactory results. 

The practice of leaving a space completely bricked in around the 
boiler to gain additional heating surface is now but seldom resorted 
to, as the tendency is to burn out that part of the boiler above the 
water line. The returning of hot gases from the uptake, across 
the top of the boiler is another defect, as its efficiency is of doubt- 
ful value. 

Another practice not to be recommended, is that of continuing 
the boiler walls above the boiler for the purpose of obtaining 
a space above the boiler for heating air for ventilation, by utilizing 
the heat escaping through the boiler covering. Should cracks be 
made in the setting or covering, there is danger of the unconsumed 
gases passing into and contaminating the air intended for ven- 
tilation. 

With this setting the fireman or engineer is obliged to crawl 
through a door and over the boiler to reach either the steam or 
safety-valve, and in case of the safety-valve blowing off to relieve 
too high pressure, the steam is carried by the warm air ducts into 



186 



THE SCHOOL HOUSE. 



the school or other rooms which receive their air from this source, 
and possibly causing excitement or a panic among the pupils. 

Plates XLI, XLII, XLIII and XLIV. — Settings for horizontal 
tubular boilers. Designed and recommended by the Hartford 
Boiler Inspection and Insurance Company. 



Q--- 



1 

't^zQ Q -j fcf 




THE SCHOOL HOUSE. 



187 




< 

H 

y< 

o 

N 

5 

X 
w 

o 


t, 

M 

en 

o 

O 

H 
O 
H 
M 

M 

Q 

P 

H 

55 
O 



188 



THE SCHOOL HOUSE. 



PLATE XLIII. 




Cross Section of Setting for One Horizontal Tubular Boiler. 



THE SCHOOL HOUSE. 



189 




o 
pq 

« 

« 
H 

H 

o 

N 

5 
o 
X 
o 
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H 

a 
o 



TABLE 15. (APPROXIMATE) AREAS 



Inches 


10 


11 


12 


13 


14 


15 


16 


17 


18 


19 


20 


21 


22 


23 


24 


25 


26 


27 


10 


.69 


.76 


.83 


.9 


.97 


1.04 


l.ll 


1.18 


1.25 


1.31 


1.38 


1.45 


1.52 


1.59 


1.66 


1.73 


1.8 


1.8 


11 


.76 


.84 


.91 


.99 


1.06 


1.14 


1.22 


1.29 


1.37 


1.45 


1.52 


1.6 


1.68 


1.75 


1.83 


1.9 


1.98 


2.0 


12 


.83 


.91 


1. 


1.08 


1.16 


1.25 


1.33 


1.41 


1.5 


1.57 


1.66 


1.75 


1.83 


1.91 


2. 


2.08 


2.16 


2.2 


13 


.9 


.99 


1.08 


1.17 


1.26 


1.35 


1.44 


1.53 


1.62 


1.71 


1.8 


1.89 


1.98 


2.07 


2.16 


2.25 


2.34 


2.4 


14 


.97 


1.06 


1.16 


1.26 


1.36 


1.47 


1.55 


1.65 


1.75 


1.84 


1.94 


2.04 


2.13 


2.23 


2.33 


2.43 


2.52 


2.6 


15 


1.04 


1.14 


1.25 


1.35 


1.47 


1.56 


1.66 


1.77 


1.87 


1.97 


2.08 


2.18 


2.29 


2.39 


2.5 


2.6 


2.7 


2.8 


16 


1.11 


1.22 


1.33 


1.44 


1.55 


1.66 


1.77 


1.88 


2. 


2.11 


2.22 


2.33 


2.44 


2.55 


2.66 


2.77 


2.88 


3. 


17 


1.18 


1.29 


1.41 


1.53 


1.65 


1.77 


1.88 


2. 


2.12 


2.24 


2.36 


2.47 


2.59 


2.71 


2.83 


2.95 


3.07 


3.11 


18 


1.25 


1.37 


1.5 


1.62 


1.75 


1.87 


2. 


2.12 


2.25 


2.37 


2.5 


2.62 


2.75 


2.87 


3. 


3.12 


3.25 


3.3' 


19 


1.31 


1.45 


1.57 


1.71 


1.84 


1.97 


2.11 


2.24 


2.37 


2.5 


2.63 


2.77 


2.9 


3.03 


3.16 


3.29 


3.43 


3.51 


20 


1.38 


1.52 


1.66 


1.8 


1.94 


2.08 


2.22 


2.36 


2.5 


2.63 


2.77 


2.91 


3.05 


3.19 


3.33 


3.47 


3.61 


3.7! 


21 


1.45 


1.6 


1.75 


1.89 


2.04 


2.18 


2.33 


2.47 


2.62 


2.77 


2.91 


3.06 


3.2 


3.35 


3.5 


3.64 


3.7 


3.91 


22 


1.52 


1.68 


1.83 


1.98 


2.13 


2.29 


2.44 


2.59 


2.75 


2.9 


3.05 


3.2 


3.36 


3.51 


3.66 


3.81 


3.97 


4.15 


23 


1.59 


1.75 


1.91 


2.07 


2.23 


2.39 


2.55 


2.71 


2.87 


3.03 


3.19 


3.35 


3.51 


3.67 


3.83 


3.99 


4.15 


4.3 


24 


1.66 


1.83 


2. 


2.16 


2.33 


2.5 


2.66 


2.83 


3. 


3.16 


3.33 


3.5 


3.66 


3.83 


4. 


4.16 


4.33 


4.5 


25 


1.73 


1.9 


2.08 


2.25 


2.43 


2.6 


2.77 


2.95 


3.12 


3.29 


3.47 


3.64 


3.81 


3.99 


4.16 


4.34 


4.51 


4.6* 


26 


1,8 


1.98 


2.16 


2.34 


2.52 


2.7 


2.8 


3.07 


3.25 


3.43 


3.61 


3.7 


3.97 


4.15 


4.33 


4.51 


4.69 


4.81 


27 


1.87 


2.06 


2.25 


2.43 


2.62 


2.81 


3. 


3.18 


3.33 


3.56 


3.75 


3.93 


4.12 


4.31 


4.5 


4.68 


4.87 


5.0( 


28 


1.94 


2.13 


2.33 


2.52 


2.72 


2.91 


3.11 


3.3 


3.5 


3.69 


3.88 


4.08 


4.27 


4.47 


4.66 


4.86 


5.05 


5.25 


29 


2.01 


2.21 


2.4 


2.61 


2.81 


3. 


3.22 


3.42 


3.62 


3.82 


4.02 


4.22 


4.43 


4.63 


4.83 


5.03 


5.23 


5.43 


30 


2.08 


2.29 


2.5 


2.7 


2.9 


3.12 


3.33 


3.54 


3.75 


3.95 


4.16 


4.37 


4.58 


4.79 


5. 


5.2 


5.41 


5.62 


31 


2.15 


2.36 


2.58 


2.79 


3.01 


3.22 


3.44 


3.66 


3.87 


4.09 


4.3 


4.52 


4.73 


4.95 


5.16 


5.38 


5.45 


5.81 


32 


2.22 


2.44 


2.66 


2.88 


3.11 


3.33 


3.55 


3.77 


4. 


4.22 


4.44 


4.66 


4.88 


5.11 


5.33 


5.55 


5.77 


6. 


33 


2.29 


2.52 


2.75 


2.97 


3.2 


3.43 


3.66 


3.89 


4.12 


4.35 


4.58 


4.81 


5.04 


5.27 


5.5 


5.72 


5.95 


6.18 


31 


2.36 


2.59 


2.83 


3.06 


3.3 


3.54 


3.77 


4. 


4.25 


4.48 


4.72 


4.95 


5.19 


5.43 


5.66 


5.9 


6.13 


6.37 


35 


2.43 


2.67 


2.91 


3.15 


3.4 


3.64 


3.88 


4.13 


4.37 


4.61 


4.86 


5.1 


5.34 


5.59 


5.83 


6.07 


6.31 


6.56 


36 


2.5 


2.75 


3. 


3.25 


3.5 


3.75 


4. 


4.25 


4.5 


4.75 


5. 


5.25 


5.5 


5.75 


6. 


6.25 


6.5 


6.75 


37 


2.56 


2.82 


3.08 


3.34 


3.59 


3.85 


4.11 


4.36 


4.62 


4.88 


5.13 


5.39 


5.65 


5.9 


6.16 


6.42 


6.68 


6.93 


38 


2.63 


2.9 


3.16 


3.43 


3.69 


3.95 


4.22 


4.48 


4.75 


5.01 


5.27 


5.54 


5.8 


6.06 


6.33 


6.59 


6.86 


7.12 


39 


2.7 


2.97 


3.25 


3.52 


3.79 


4.06 


4.34 


4.6 


4.87 


5.14 


5.41 


5.68 


5.95 


6*.22 


6.5 


6.77 


7.04 


7.24 


40 


2.77 


3.05 


3.33 


3.61 


3.88 


4.16 


4.44 


4.72 


5. 


5.27 


5.55 


5.83 


6.11 


6.38 


6.66 


6.94 


7.22 


7.5 


41 


2.84 


3.13 


3.41 


3.7 


3.98 


4.27 


4.55 


4.84 


5.12 


5.4 


5.69 


5.97 


6.26 


6.54 


6.83 


7.11 


7.4 


7.68 


42 


2.91 


3.2 


3.5 


3.79 


4.08 


4.37 


4.66 


4.95 


5.25 


5.54 


5.83 


6.12 


6.41 


6.7 


7. 


7.29 


7.58 


7.87 


43 


2.98 


3.28 


3.58 


3.88 


4.18 


4.47 


4.77 


5.07 


5.37 


5.67 


5.97 


6.29 


6.56 


6.86 


7.16 


7.46 


7.76 


8.06 


44 


3.05 


3.36 


3.66 


3.97 


4.27 


4.5S 


4.88 


5.19 


5.5 


5.8 


6.11 


6.41 


6.72 


7.02 


7.33 


7.63 


7.94 


8.25 


45 


3.12 


3.43 


3.75 


4.06 


4.37 


4.68 


5. 


5.31 


5.62 


5.93 


6.25 


6.56 


6.87 


7.18 


7.5 


7.81 


8.12 


8.43 



DIMENSIONS IN INCHES. 



AREAS IN SQUARE FEET. 



OF RECTANGULAR OPENINGS. 



28 


29 


30 


31 


32 


33 


34 


35 


36 


37 


38 


39 40 


41 


42 


43 


44 


45 


Inches 


1.94 


2.01 


2.08 


2.15 


2.22 


2.29 


2.36 


2.43 


2.5 


2.56 


2.63 


2.7 


2.77 


2.84 


2.91 


2.98 


3.05 


3.12 


10 


2.13 


2.21 


2.29 


2.36 


2.44 


2.52 


2.59 


2.67 


2.75 


2.82 


2.9 


2.97 


3.05 


3.13 


3.2 


3.28 


3.36 


3.43 


11 


2.33 


2.4 


2.5 


2.58 


2.66 


2.75 


2.83 


2.91 


3. 


3.08 


3.16 


3.25 


3.33 


3.41 


3.5 


3.58 


3.66 


3.75 


12 


2.52 


2.61 


2.7 


2.79 


2.88 


2.97 


3.06 


3.15 


• 3.25 


3.34 


3.43 


3.52 


3.61 


3.7 


3.79 


3.88 


3.97 


4.06 


13 


2.72 


2.81 


2.9 


3.01 


3.11 


3.2 


3.3 


3.4 


3.5 


3.59 


3.69 


3.79 


3.88 


3.98 


4.08 


4.18 


4.27 


4.37 


14 


2.91 


3. 


3.12 


3.22 


3.33 


3.43 


3.54 


3.64 


3.75 


3.85 


3.95 


4.06 


4.16 


4.27 


4.37 


4.47 


4.58 


4.68 


15 


3.11 


3.22 


3.33 


3.44 


3.55 


3.66 


3.77 


3.88 


4. 


4.11 


4.22 


4.34 


4.44 


4.55 


4.66 


4.77 


4.88 


5. 


16 


3.3 


3.42 


3.54 


3.66 


3.77 


3.89 


4. 


4.13 


4.25 


4.36 


4.48 


4.6 


4.72 


4.84 


4.95 


5.07 


5.19 


5.31 


17 


3.5 


3.62 


3.75 


3.87 


4. 


4.12 


4.25 


4.37 


4.5 


4.62 


4.75 


4.87 


5. 


5.12 


5.25 


5.37 


5.5 


5.62 


18 


3.G9 


3.82 


3.95 


4.09 


4.22 


4.35 


4.48 


4.61 


4.75 


4.88 


5.01 


5.14 


5.27 


5.4 


5.54 


5.67 


5.8 


5.93 


19 


3.88 


4.02 


4.16 


4.3 


4.44 


4.58 


4.72 


4.86 


5. 


5.13 


5.27 


5.41 


5.55 


5.69 


5.83 


5.97 


6.11 


6.25 


20 


4.08 


4.22 


4.37 


4.52 


4.66 


4.81 


4.95 


5.1 


5.25 


5.39 


5.54 


5.68 


5.83 


5.97 


6.12 


6.29 


6.41 


6.56 


21 


4.27 


4.43 


4.58 


4.73 


4.88 


5.04 


5.19 


5.34 


5.5 


5.67 


5.8 


5.95 


6.11 


6.26 


6.41 


6.56 


6.72 


6.87 


22 


4.47 


4.63 


4.79 


4.95 


5.11 


5.27 


5.43 


5.59 


5.75 


5.9 


6.06 


6.22 


6.38 


6.54 


6.7 


6.86 


7.02 


7.18 


23 


4.66 


4.83 


5. 


5.16 


5.33 


5.5 


5.66 


5.83 


6. 


6.16 


6.33 


6.5 


6.66 


6.83 


7. 


7.16 


7.33 


7.5 


24 


4.86 


5.03 


5.2 


5.38 


5.55 


5.72 


5.9 


6.07 


6.25 


6.42 


6.59 


6.77 


6.94 


7.11 


7.29 


7.46 


7.63 


7.81 


25 


5.05 


5.23 


5.41 


5.45 


5.77 


5.95 


6.13 


6.31 


6.5 


6.68 


6.86 


7.04 


7.22 


7.4 


7.58 


7.76 


7.94 


8.12 


26 


5.25 


5.43 


5.62 


5.81 


6. 


6.18 


6.37 


6.56 


6.75 


6.93 


7.12 


7.24 


7.5 


7.68 


7.87 


8.06 


8.25 


8.43 


27 


5.44 


5.63 


5.83 


6.02 


6.22 


6.4 


6.61 


6.8 


7. 


7.19 


7.38 


7.58 


7.77 


7.97 


8.16 


8.36 


8.55 


8.75 


28 


5.63 


5.84 


6.04 


6.24 


6.44 


6.64 


6.84 


7.04 


7.25 


7.45 


7.65 


7.8 


8.05 


8.25 


8.45 


8.65 


8.86 


9.06 


29 


5.83 


6.04 


6.25 


6.45 


6.66 


6.87 


7.08 


7.29 


7.5 


7.7 


7.91 


8.12 


8.33 


8.54 


8.75 


8.95 


9.16 


9.37 


30 


6.02 


6.24 


6.45 


6.67 


6.88 


7.1 


7.31 


7.53 


7.75 


7.96 


8.18 


8.39 


8.61 


8.82 


9.04 


9.25 


9.47 


9.68 


31 


6.22 


6.44 


6.66 


6.88 


7.1 


7.33 


7.5") 


7.77 


8. 


8.22 


8.44 


8.66 


8.88 


9.11 


9.33 


9.55 


9.77 


10. 


32 


6.4 


6.64 


6.87 


7.1 


7.33 


7.56 


7.7!) 


8.02 


8.25 


8.47 


8.7 


8.93 


9.16 


9.39 


9.62 


9.85 


10.08 


10.31 


33 


6.61 


6.84 


7.08 


7.31 


7.55 


7.79 


8.02 


8.26 


8.5 


8.73 


8.97 


9.2 


9.44 


9.68 


9.91 


10.15 


10.38 


10.62 


34 


8.8 


7.04 


7.29 


7.53 


7.77 


8.02 


8.26 


8.5 


8.75 


9. 


9.23 


9.47 


9.72 


9.89 


10.2 


10.45 


10.69 


10.93 


35 


7. 


7.25 


7.5 


7.75 


8. 


8.25 


8.5 


8.75 


9. 


9.25 


9.5 


9.75 


10. 


10.25 


10.5 


10.75 


11. 


11.25 


36 


;.\'.> 


7.45 


7.7 


7.96 


8.22 


8.47 


8.73 


9. 


9.25 


9.5 


9.76 


10.02 


10.27 


10.5;; 


10.79 


11.04 


1 1 .3 


11.56 


37 


JM 


7.65 


7.91 


8.18 


8.44 


8.7 


8.97 


9.23 


9.5 


9.76 


10.02 


10.29 


10.55 


10.81 


11. OS 


11.34 


11.61 


11.87 


38 


r.58 


7.8 


8.12 


8.39 


8.66 


8.93 


9.2 


9.47 


9.75 


10.02 


10.29 


10.56 


10.83 


11.1 


11.37 


11.64 


11.91 


12.11 


39 


: .77 


8.05 


8.33 


8.61 


8.88 


9.16 


9.44 


9.72 


10. 


10.27 


10.55 


10.83 


11.11 


11.38 


11.66 


11.94 


12.12 


12.5 


40 


r .97 


8.25 


8.54 


8.82 


9.11 


9.39 


9.68 


9.89 


10.25 


L0.53 


10.81 


11.1 


11.38 


11.67 


11.95 


L2.24 


12.52 


12.81 


41 


!.16 


8.45 


8.75 


9.04 


9.33 


9.62 


9.91 


10.2 


10.5 


in.::) 


11.08 


11.37 


11.66 


11.95 


12.25 


12.54 


12.83 


L3.12 


42 


;.:',6 


8.65 


8.95 


9.25 


9.55 


9.85 


10.15 


L0.45 


10.75 


11.04 


11.34 


11.64 


11.94 


12.24 


12.54 


12.84 


L3.13 


13.43 


43 


:.55 


8.86 


9.16 


9.47 


9.77 


10.08 


10.38 


10.69 


11. 


11.3 


11.61 


11.9 J 


12.12 


12.52 


12.83 


13.13 


13.44 


13.75 


44 


.75 

...... 


9.06 


9.37 


9.68 


10. 


10.31 


10.62 


10.93 


11.25 


11.56 


11.87 


12.11 12.5 


12.81 


13.12 


L3.43 


1."..:;. 14.06 45 



NO DEDUCTION HAS BEEN MADE HERE FOR REGISTERS OR GRILLS. 



102 



THE SCHOOL HOUSE. 



TABLE 16. 

Areas and Circumference of Circles. 







Circum- 






Circum- 






Circum- 


Diam. 


Area. 


ference. 


Diam. 


Area. 


ference. 


Diam. 


Area. 


ference. 


In. 


Sq. Ft. 


Ft. 


In. 


Sq. Ft. 


Ft. 


In. 


Sq. Ft. 


Ft. 


1 


.0055 


.2618 


29 


4.587 


7.592 


57 


17.72 


14.92 


2 


.0218 


.5236 


30 


4.909 


7.854 


58 


18.35 


15.18 


3 


.0491 


.7854 


31 


5.241 


8.116 


59 


18.99 


15.45 


4 


.0873 


1.047 


32 


5.585 


8.378 


60 


19.63 


15.71 


5 


.1364 


1.309 


33 


5.940 


8.639 


61 


20.29 


15 97 


6 


.1964 


1.571 


34 


6.305- 


8.901 


62 


20.97 


16.23 


7 


.2673 


1.833 


35 


6. £81 


9.163 


63 


21.65 


16.49 


8 


.3491 


2.094 


36 


7.069 


9.425 


64 


22.34 


16.76 


9 


.4418 


2.356 


37 


7.467 


9.686 


65 


23.04 


17.02 


10 


.5454 


2.618 


38 


7.876 


9.948 


66 


23.76 


17.28 


11 


.6600 


2.880 


39 


8.276 


10.21 


67 


24.48 


17.54 


12 


.7854 


3.142 


40 


8.727 


10.47 


68 


25.22 


17.80 


13 


.9218 


3.403 


41 


9.168 


10.73 


69 


25.97 


18.06 


14 


1.069 


3.665 


42 


9.621 


10.99 


70 


26.73 


18.33 


15 


1.227 


3.927 


43 


10.08 


11.26 


71 


27.49 


18.59 


16 


1.396 


4.189 


44 


10.56 


11.52 


72 


28.27 


18.85 


17 


1.576 


4.451 


45 


11.04 


11.78 


73 


29.07 


19.11 


18 


1.767 


4.712 


46 


11.54 


12.04 


74 


29.87 


19.37 


19 


1.969 


4.974 


47 


12.05 


12.30 


75 


30.68 


19 63 


20 


2.182 


5.236 


48 


12.57 


12.57 


76 


31.50 


19.90 


21 


2.405 


5.498 


49 


13.10 


12.86 


77 


32.34 


20.16 


22 


2.640 


5.760 


50 


13.64 


13.09 


78 


33.18 


20.42 


23 


2.885 


6.021 


51 


14.19 


13.35 


79 


34.04 


20.68 


24 


3.142 


6.283 


52 


14.75 


13.61 


80 


34.91 


20.94 


25 


3.409 


6.545 


53 


15.32 


13.88. 


81 


35.78 


21.21 


26 


3.687 


6.807 


54 


15.90 


14.14 


82 


36.67 


21.47 


27 


3976 


7.069 


55 


16.50 


14.40 


83 


37.57 


21.73 


28 


4.276 


7.330 


56 


17.10 


14.66 


84 


38.48 


21.99 



THE SCHOOL HOUSE. 



198 























































^ & ^ -S ^ * 




























8 5^ § ^ 
























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cn. 


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93 


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p. 


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99 


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CO 






O 




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c^ 


cr 






/ 
























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t 




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x 


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la 


1- 


r . 


93 


- 


























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CO 


•"' 


cm 


SN 


00 


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"" 


CO 


X 


ga 


2 


5 


03 


CO 


e 


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tl 
c: 


OS 


m 


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gg 


M 


93 


p. 


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■" 





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'£. 


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s 


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s 


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x. 


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- 










■ 


























r'-* 


- 


w 


■*< 


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f 


- 


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g 




L- 


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3 


g 




90 




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2 


























































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yi 


CO 


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to 


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cc 


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f, 


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09 


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X 


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1: 


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A 




p. 


00 










































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CM 


■" 


Cr - 


JSJ 


Vi 


GO 


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cc 


~ 


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r 


s 


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O 
X 


EX 


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ec 


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a 


t* 


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_ 




^ 


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c ~ 


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194 



THE SCHOOL HOUSE. 



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THE SCHOOL HOUSE. 



195 



TABLE 19. 

Capacity of Pipes and Registers. 

ROUND PIPES. 



Diameter 


Area in 


Diameter 


Area in 


Diameter 


Area in 


of Pipe 


Sq. Inches. 


of Pipe. 


Sq. Inches. 


of Pipe. 


Sq. Inches. 


7 in. 


38 


12 in. 


113 


22 in. 


380 


8 in. 


50 


14 in. 


154 


24 in. 


452 


9 in. 


63 


16 in. 


201 


20 in. 


531 


10 in. 


78 


18 in. 


254 


28 in. 


616 


11 in. 


95 


20 in. 


314 


30 in. 


707 



REGISTERS. 



Size of 


Capacity in 


Size of 


Capacity in 


Size of 


Capacity in 
Sq. Inches. 


Opening. 


Sq. Inches. 


Opening. 


Sq. Inches. 


Opening. 


6X10 


40 


10X14 


93 


20X20 


267 


8X10 


53 


10X16 


107 


20 X 24 


320 


8X12 


64 


12X15 


120 


20X26 


347 


8X15 


80 


12X19 


152 


21X29 


406 


9X12 


72 


14X22 


205 


27X27 


486 


9X14 


84 


15X25 


250 


27X38 


684 


10X12 


80 


16X24 


256 


30X30 


600 



ROUND REGISTERS. 



1 

Size of 
Opening. 


Capacity in 
Sq. Inches. 


Size of 
Opening. 


Capacity in 
Sq. Inches. 


Size of 
Opening. 


Capacity in 
Sq. Inches. 


7 in. 

8 in. 

9 in 
10 in. 


26 
33 
42 
52 


12 in. 
14 in. 
16 in. 
18 in. 


75 
103 
134 
169 


20 in. 
24 in. 
30 in. 
36 in. 


209 
301 
471 
679 



DIMENSIONS OF CAST-IRON REGISTERS. 

(TUTTLE AND BAILEY.) 



Size. 
Inches. 



10X12 
10X14 
10X16 
12X15 
12X16 
12X19 
14X18 
14X22 
15X25 
16X16 
16X20 
16X21 



Net Area. 
Square Feet. 



.55 

.64 

.74 

.83 

.88 

1.05 

1.16 

1.42 

1.73 

1.18 

1.48 

1.55 



Size. 

Inches. 



16X24 
16X26 
18X24 
18X30 
20X20 
20X24 
20X26 
21X29 
24X32 
27X27 
27X38 
30X30 



Net Area. 
Square Feet. 



1.77 
1.92 
2.00 
2.50 
1.85 
2.22 
2.41 
2.82 
3.55 
3.37 
4.75 
4.16 



196 



THE SCHOOL HOUSE. 



TABLE 20. 
Weights of and Q Steel per Lineal Foot 
(Based o?i 489.6 lbs. fer cubic foot.) 



Size. 


Wt. of • 


Wt. of ■ 


Size. 


Wt. of # 


Wt. of ■ 


Size. 


Wt. of • 


Wt.ofH 


Inches. 


1 ft. long 


1 ft. long. 


Inches. 


1 ft. long 


1 ft. long 


Inches 


1 ft. long. 


1ft. long. 


0ft 


.0026 


.0033 


3 


24.03 


30.60 


6 


96.14 


122.4 


oft 


.0104 


.0133 


3ft 


25.04 


31.89 


eft- 


98.14 


125.0 


04 


.0417 


.0531 


H 


26.08 


33.20 


el 


100.2 


127.6 


oft 


.0938 


.1195 


3ft 


27.13 


34.55 


6ft 


102.2 


130.2 


01 


.1669 


.2123 


H 


28.20 


35.92 


6j 


104.3 


132.8 


oft 


.2608 


.3333 


°1 6 


29.30 


37.31 


6-5- 

°1 6 


106.4 _ 


135.5 


OS 


.3756 


.4782 


H 


30.42 


38.73 


6 a 

u 8 


108.5 


138.2 


Oft 


.5111 


.6508 


3ft 


31.56 


40.18 


eft- 


110.7 


140.9 


oi 


.6676 


.8500 


H 


32.71 


41.65 


ei 


112.8 


143.6 


0ft 


.8449 


1.076 


d 16 


33.90 


43.14 


"in 


114.9 


146.5 


0| 


1.043 


1.328 


3 A 

'8 


35.09 


44.68 


6£ 


117.2 


149.2 


OH 


1.262 


1.608 


Q1X 
°16 


36.31 


46.24 


Hh' 


119.4 


152.1 


of 


1.502 


1.913 


3f 


37.56 


47.82 


6* 


121.7 


154.9 


oil 


1.763 


2.245 


Sit 


38.81 


49.42 


611 


123.9 


157.8 


o& 


2.044 


2.603 


°8 


40.10 


51.05 


«s 


126.2 


160.8 


rU-5 


2.347 


2.989 


3l6 


41.40 


52.71 


oil 


12S. 5 


163.6 


1 


2.670 


3.400 


4 


42.73 


54.40 


7 


130.9 


166.6 


1ft 


3.014 


3.838 


4ft 


44.07 


56.11 


n 


135.6 


172.6 


li 


3.379 


4.303 


41 


45.44 


57.85 


71 


140.4 


178.7 


1ft 


3.766 


4.795 


4ft 


46.83 


59.62 


n 


145.3 


184.9 


H 


4.173 


5.312 


4| 


48.24 


61.41 


n 


150.2 


JL91.3 


ift 


4.600 


5.857 


4ft 


49.66 


63.23 


u 


155.2 


197.7 


if 


5.019 


6.428 


4| 


51.11 


65.08 


n 


160.3 


204.2 


ift 


5.518 


7.026 


A..1- 
*16 


52.58 


66.95 


7 L 

' 8 


165.6 


210.8 


li 


6.008 


7.650 


4-L 
*2 


54.07 


68.85 


8 


171.0 


217.6 


1-2- 
L l 6 


6.520 


8.301 


4ft 


55 59 


70.78 


«1 


176.3 


224.5 


l| 


7.051 


8.978 


4f 


57.12 


72.73 


81 


181.8 


231.4 


iH 


7.604 


9.682 


*tt 


58.67 


74.70 


8| 


187.3 


238.5 


if 


8.178 


10.41 


44 


60.25 


76.71 


81 


193.0 


245.6 


1 16 


8.773 


11.17 


4!!- 


61.84 


78.74 


8f 


198.7 


252.9 


l 1 
1 8 


9.388 


11.95 


*i 


63.46 


80.81 


8| 


204.4 


260 3 


1 16 


10.02 


12.76 


*16 


65.10 


82.89 


8| 


210.3 


267.9 


2 


10.68 


13.60 


5 


66.76 


85.00 


9 


216.3 


275.4 


2ft 


11.36 


14.46 


K.L. 
"1 6 


68.44 


87.14 


91 


222.4 


283 2 


21 


12.06 


15.35 


H 


70.14 


89.30 


n 


228.5 


290.9 


2ft 


12.78 


16.27 


"16 


71.86 


91.49 


n 


234.7 


298.9 


2i 


13.52 


17.22 


H 


73.60 


93.72 


91 


241.0 


306.8 


2 ft 


14.28 


18.19 


5ft 


75.37 


95.96 


H 


247.4 


315.0 


2f 


15.07 


19.18 


6| 


77.15 


98.23 


9f 


253.9 


323.2 


2ft 


15.86 


20.20 


5ft 


78.95 


100.5 


91 


260.4 


331.6 


2i 


16.69 


21.25 


5i • 


80.77 


102.8 


10 


267.0 


340.0 


2ft 


17.53 


22.33 


"16 


82.62 


105.2 


101 


280.6 


357 2 


a* 


18.40 


23.43 


5| 


84.49 


107.6 


101 


294.4 


374.9 


2n 


19.29 


24.56 


5H 


86.38 


110.0 


10| 


308 6 


392.9 


2| 


20.20 


25.00 


6f 


88.29 


112.4 


11 


323.1 


411.4 


211 


21.12 


26.90 


J 1 6 


90.22 


114 9 


111 


337.9 


430.3 


8i 


22.07 


28.10 


5£ 


92.17 


117.4 


Hi 


353.1 


449 6 


2H 


23.04 


29.34 


51f 


94.14 


119.9 


ii| 


368.6 


489.4 



These figures represent the theoretical weights of steel. Iron will run 
about 2 per cent lighter. 



THE SCHOOL HOUSE. 



97 



TABLE 21. 
Standard Gauges. 





U.S. STANDARD GAUGE. 




BIRMINGHAM GAUGE. 


No. of 
Gauge 


Thickness in Inches. 


Weight Square Foot. 


No. oi 

Gauge 


Thick- 
ness in 
Inches 


Weight 


Sq. Foot. 


• fractions 


Decimals. 


Iron. 


Steel. 


Iron. 


1 Steel. 


7-0's 
6-0's 


1 

2 

15. 
32 


.5 
•46875 


20.00 

18.75 


20.4 
19.125 




— 


- 


5-0's 

0000 

000 

00 



1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 


1 6 
JLi 
3 2 

a 


.4375 

.40625 

.375 

.34375 

.3125 

.28125 

.265625 

.25 

.234375 


17.50 
16.25 


17.85 
16.575 


0000 


.454 


18.22 


18.46 


8 
11 
3 2 
-5. 
16 

A 

i 

4 

15. 
64 
7 


15. 

13.75 
12.50 
11.25 
10.625 
10. 
9.375 


15.30 
14.025 
12.75 
11.475 
10.8375 
10.2 
9.5625 


000 

00 



1 

2 
3 
4 


.425 

.38 

.34 

.3 

.284 

.259 

.238 


17.05 
L6.25 

13.64 
12.04 
11.40 
10.39 
9.55 


17.28 
15.45 
13.82 
12.20 
11.55 
10.53 
9.68 


32 
li 
64 
-3_ 

1 6 ■ 
^ 1_ 


.21875 
.203125 

.1875 


8.75 

8.125 

7.5 


8.925 

8.2875 

7.65 


5 
6 

7 


.22 

.203 
.18 


8.83 
8.15 
7.22 


8 95 
8.25 
7.32 


64 
-5. 
32 

.a. 

64 


.171875 


6.875, 


7.0125 


8 


.165 


6.62 


6.71 


.15625 
.140625 


6.25 
5.625 


6.375 
5.7375 


9 
10 


.148 
.134 


5.94 
5.38 


6.02 
5.45 


8 
-I- 
64 

* 


.125 


5. 


5.1 


11 


.12 


4.82 


4.88 


12 


.109375 


4.375 


4.625 


12 


.109 


4.37 


4.43 


13 


.09375 


3.75 


3.825 


13 


.095 


3.81 


3.86 


14 


5 . 
64 


.078125 


3.125 


3.1875 


14 


.083 


3.33 


3.37 


15 


T2"8 


.0703125 


2.8125 


2.86875 


15 


.072 


2.89 


2.93 


16 


_1- 
1 6 


.0625 


2.5 


2.55 


16 


.065 


2.61 


2.64 


17 


9 

160 


.05625 


2.25 


2.295 


17 


.058 


2.33 


2.36 


18 


-1- 
20 


.05 


2. 


2.04 


18 


.049 


1.97 


1.99 


19 


T60 


.04375 


1.75 


1.785 


19 


.042 


1.69 


1.71 


20 


-3. 

80 


.0375 


1.50 


1.53 


20 


035 


1.40 


1.42 


21 


_ll- 
320 


.034375 


1.375 


1.4025 


21 


.032 


1.28 


1.30 


22 


32 


.03125 


1.25 


1.275 


22 


028 


1.12 


1.14 


23 


_8_ 
320 


.028125 


1.125 


1.1475 


23 


.025 


1.00 


1.02 


24 


4_0 


.025 


1. 


1.02 


24 


.022 


.883 


.895 


25 


3^0 


.021875 


.865 


.8925 


25 


.02 


.803 


.813 


26 


_3_ 

160 


.01875 


.75 


.765 


26 


.018 


.722 


.732 


27 


-11_ 
640 


.0171875 


.6875 


.70125 


27 


.016 


.642 


.651 


28 


-1. 
64 


.015625 


.625 


.6375 


28 


.014 


.562 


.569 


29 


. 9 . 
640 


.0140625 


.5625 


.57375 


29 


.013 






30 


_1- 

80 


.0125 


.5 


.51 


30 


.012 







31 


64 


.010985 


.4375 


44625 


31 


.01 







32 


_13_ 
1280 


.01045625 


.40625 


.414375 


32 


.009 







33 


_3_ 
320 


.009375 ' 


.375 


.3825 


33 


.008 







34 


_L1_ 
1 280 


.008593:5 


.34375 


.350625 


34 


.007 







35 


_5_ 
640 


.0078125 


.3125 


.31875 


35 


.005 








36 


a_ 

12 80 


.00703125 


.28125 


.286875 


36 


.004 







37 


_17_ 
2560 


.00664062 


.265625 


.2709375 


37 









38 


160 


.00625 


.25 


.255 


— 


— 


— 


— 



All sheets of iron and steel are rolled to U.S. standard gauge unless 
otherwise ordered- 

The low temperature (as compared with iron) at which steel plates have 
to be finished, causes a slight springing of the rolls, leaving the plate thicker 
in the center than on the edge. This is especially noticeable in plates less 
than ft i nc h thick and over 66 inches wide, which* may be of full thickness 
on the edge and yet be as much as ]/ % inch thicker in the middle. 



198 



THE SCHOOL HOUSE. 



TABLE 22 
Estimated Weights of Galvanized Sheets. 



U.S. Stan- 
dard Gauge 


10 


12 


14 


16 


18 


20 


22 


24 


25 


26 


27 


28 


29 


30 


Weight per / 
sq.ft., lbs ( 


5.781 


4.531 


3.281 


2.656 


2.156 


1.656 


1406 


1.156 


1.031 


.9062 


.8437 


.7812 


.7187 


.6562 


Weight per / 
sq. ft., oz. ( 


92.5 


72.5 


52.5 


42.5 


34.5 


26.5 


22.5 


18.5 


16.5 


14.5 


13.5 


12.5 


11.5 


10.5 






























Size of 
Sheet 










We 


IGHT 


of Sheet— 


-Pounds 










24 x 72 


69 


54 


39 


32 


26 


20 


17 


14 


12 


11 


10 


9 


9 


8 


24 x 84 


81 


63 


46 


37 


30 


23 


20 


16 


14 


13 


12 


11 


10 


9 


24 x 96 


93 


73 


53 


43 


35 


27 


23 


19 


17 


15 


14 


13 


12 


11 


24 x 120 


116 


91 


66 


53 


43 


33 


28 


23 


21 


18 


17 


16 


14 


13 


26 x 72 


75 


59 


43 


35 


28 


22 


18 


15 


13 


12 


11 


10 


9 


9 


26 x 84 


88 


69 


50 


40 


33 


25 


21 


18 


16 


14 


13 


12 


11 


10 


26 x 96 


100 


79 


57 


46 


37 


29 


24 


20 


18 


16 


15 


14 


12 


11 


26 x 120 


125 


98 


71 


58 


47 


36 


30 


25 


22 


20 


18 


17 


16 


14 


28 x 72 


81 


63 


46 


37 


30 


23 


20 


16 


14 


13 


12 


11 


10 


9 


28 x 84 


94 


74 


54 


43 


35 


27 


23 


19 


17 


15 


14 


13 


12 


11 


28 x 96 


108 


85 


61 


50 


40 


31 


26 


22 


19 


17 


16 


15 


13 


12 


28 x 120 


135 


106 


77 


62 


50 


39 


33 


27 


24 


21 


20 


18 


17 


15 


30 x 72 


87 


68 


49 


40 


32 


25 


21 


17 


15 


14 


13 


12 


11 


10 


30 x 84 


101 


79 


57 


46 


38 


29 


25 


20 


18 


16 


15 


14 


13 


11 


30 x 96 


116 


91 


66 


53 


43 


33 


28 


23 


21 


18 


17 


16 


14 


13 


30 x 120 


145 

104 


113 

82 


82 
59 


66 

48 


54 
39 


41 

30 


35 


29 


26 


23 


21 


20 


18 


16 


36 x 72 


25 


21 


19 


16 


15 


14 


13 


12 


36 x 84 


121 


95 


69 


55 


45 


35 


30 


24 


22 


19 


18 


16 


15 


14 


36 x 96 


139 


109 


79 


64 


52 


40 


34 


28 


25 


22 


20 


19. 


17 


16 


36 x 120 


173 


136 


98 


80 


65 


50 


42 


35 


31 


27 


25 


23 


22 


20 


42 x 72 


121 


95 


71 


56 


45 


34 


29 


24 


22 


19 


18 


16 


15 


14 


42 x 84 


142 

162 


111 

127 


80 
92 


65 

74 


53 


41 


34 
39 


28 
32 


25 
29 


22 
25 


21 
24 


19 
22 


18 
20 


16 


42 x 96 


60 


46 


18 


42 x 120 


202 


L59 


115 


93 


75 
52 


58 
40 


49 
34 


41 

28 


36 
25 


33 

22 


29 
20 


27 
19 


25 

17 


23 


48 x 72 


139 


109 


79 


64 


16 


48 x 84 


162 


125 


92 


74 


60 


46 


39 


32 


29 


25 


24 


22 


20 


18 


48 x 96 


185 


145 


105 


85 


69 


55 


45 


37 


33 


29 


27 


25 


23 


21 


48 x 120 


231 


181 


131 


106 


86 


66 


56 


46 


41 


36 


34 


31 


29 





THE SCHOOL HOUSE. 



199 



TABLE 23. 

Circumferences of Circles. 

Comprehending Diameters Used by Boiler Makers. 



Diameter in 


Circumference 


Area in 


Diameter in 


Circumference 




Inches. 


in Inches. 


Sq. Inches. 


Inches. 


in Inches 


Sq. Inches 


12 


. 37f 


113 


58 


1824 


2642 


14 


44 


154 


60 


188! 


2827! 


16 


504 


201 


62 


194| 


3019 


18 


56* 


254! 


64 


201 


3217 


20 


62$ 


3144 


66 


207} 
213| 


3421! 


22 


69 


3804 


68 


3631| 


24 


75f 


452f 


70 


2195 


3848! 


26 


81| 


531 


72 


2264 


4071! 


28 


875 


615| 


74 


232g 


43005 


30 


94j 


7065 


76 


238 & 


4536! 


32 


1004 


804| 


78 


2445 


44788 


34 


1063 


908 


80 


251! 


5026! 


36 


113 


10175 


82 


257! 


5281 


38 


1191 


11344 


84 


263J 


5541 1 


40 


125| 


1256| 


86 


2704 


58085 


42 


1311 ' 


1385! 


88 


276! 


60824 


44 


1384 


1520! 


90 


282| 


6361f 


46 


H4| 


1662 


92 


289 


6647| 


48 


150f 


1809! 


94 


295! 


6939f 


50 


157 


1963! 


96 


301! 


7238! 


52 


163i 


2123$ 


98 


3075 


7543 


54 


169| 


2290| 


100 


314! 


7854 


56 


175J 


2463 


102 


320| 


8171| 



Boilermakers usually add three times the thickness of the plate to length 
of iron for the take-up in rolling; also add for laps, single or double riveting. 



TABLE 24. 
Number of Tubes Usually Put in Return Tubular Boilers. 



Hand-holes Under Tubes. 


Manhole U 


NDER Tu 


BES. 


Diam. 


2A-Inch 
Tubes. 


3-Inch 


3J-Inch 
Tubes. 


4-Inch 


Diar 


3-Inch 


3J-Inch 
Tubes. 


4-Inch 


Boiler. 


Tubes. 


Tubes. 




Tubes. 


Tubes. 


36 


38 


26 




_ 


_ 


_ 


_ 


_ 


42 


52 


38 


- 


- 


42 


- 


22 


18 


44 


_ 


38 


34 


22 


44 


28 


26 


20 


48 


_ 


52 


38 


34 


48 


44 


28 


26 


54 


_ 


54 


44 


34 


54 


56 


44 


36 


60 


_ 


82 


64 


54 


60 


62 


54 


44 


66 


_ 


_ 


72 


54 


66 


- 88 


66 


54 


72 


_ 


_ 


92 


72 


72 


124 


86 


70 


- 


- 


- 


- 


- 


78 


132 


100 


84 



200 THE SCHOOL HOUSE. 

TABLE 25. 
Dimensions of Standard Wrought Iron Pipe. 



Inches. 


Actual 
Diameter. 




Circumference. 
Inches. 


Length pf Pipe 
in feet per 
Square Foot 
of Surface. 


Area. 
Square Inches. 


Nominal 


















Inside 
Diam. 


Inside. 


Outside. 


H 


Internal. 


External. 


Inside. 


Outside. 


Internal. 


External. 


i 


.27 


.40 


.07 


.84 


1.27 


14.15 


9.44 


.06 


.12 


± 


.36 


.54 


.08 


1.14 


1.69 


10.50 


7.07 


.10 


.22 


8 


.49 


.67 


.09 


1.55 


2.12 


7.67 


5.65 


.19 


.35 


2 


.62 


.84 


.10 


1.95 


2.65 


6.13 


4.50 


.30 


.55 


3 

4 


.82 


1.05 


.11 


2.58 


3.29 


4.63 


3.63 


.53 


.86 


1 


1.04 


1.31 


.13 


3.29 


4.13 


3.67 


2.90 


.86 


1.35 


H 


1.38 


1.66 


.14 


4.33 


5.21 


2.76 


2.30 


1.49 


2.16 


H 


1.61 


1.90 


.14 


5.06 


5.96 


■ 2.37 


2.01 


2.03 


3.83 


2 


2.06 


2.37 


.15 


6.49 


7.46 


1.84 


1.61 


3.35 


4.43 


2Jr 


2.46 


2.87 


.20 


7.75 


9.03 


1.54 


1.32 


4.78 


6.49 


3 


3.06 


3.50 


.21 


9.63 


10.96 


1.24 


1.09 


7.38 


9.62 


31 


3.56 


4.00 


.22 


11.14 


12.56 


1.07 


.95 


9.83 


12.50 


4 


4.02 


4.50 


.23 


12.64 


14.13 


.94 


.84 


12.73 


15.90 


4 1 


4.50 


5.00 


.24 


14.15 


15.70 


.84 


.76 


15.93 


19.63 


5 


5.04 


5.56 


.25 


15.84 


17.47 


.75 


.62 


19.99 


24.30 


6 


6.06 


6.62 


.28 


19.05 


20.81 


.63 


.57 


28.88 


34.47 


7 


7.02 


7.62 


.30 


22.06 


23.95 


.54 


.50 


38.53 


45.66 


8 


7.98 


8.62 


.32 


25.07 


27.09 


.47 


.44 


50.03 


58.42 


9 


9.00 


9.6$ 


.34 


28.27 


30.43 


.42 


.40 


63.63 


73.71 


10 


10.01 


10.75 


.36 


31.47 


33.77 


.38 


.35 


78.83 


90.79 


11 


11.00 


11.75 


.37 


34.55 


36.91 


.34 


.32 


95.03 


108.43 


12 


12.00 


12.75 


.37 


37.70 


40.05 


.32 


.30 


113.09 


127.67 


13 


13.25 


14.00 


.37 


41.62 


43.98 


.29 


.27 


137.88 


153.94 


14 


14.25 


15.00 


.37 


44.76 


47.12 


.27 


.25 


159.48 


167.71 


15 


15.40 


16.00 


.28 


48,48 


50.26 


.25 


.24 


187.04 


201.06 



TABLE 26. 

Expansion of Metals. 

The linear .Expansion, or Extension of Metals for One Degree Rise 
in Temperature. 



Material. 


Increase of Length in 
One Foot for an Increase 
in Temperature of 1° F. 


Material. 


Increase of Length in 
One Foot for an Increase 
in Temperature of 1° F. 


Cast-Iron 
Wrought-Iron 
Steel Tubes 
Copper 


.0000740 
.0000823 
.0000719 
.0001146 


Brass 
Zinc 
Lead 
Tin 


.0001244 
.0001961 
.0001900 
.0001692 



To find the amount of expansion or contraction of a bar or pipe of 
given length, which will be caused by a given change in tempera- 
ture, multiply the length in feet by the number of degrees of change 
in temperature. Multiply this product by the co-efficient given in 



THE SCHOOL HOUSE. 2 01 

the table for the material employed. The result will be the ch 
in length in inches. 

Iron pipes which are used in steam and hot-water fitting expand 
about one and one-half inches for 100 feet in length. 

In long lines of pipe this expansion must be provided for; other- 
wise it will make trouble h\ breaking connections or shoving appa- 
ratus out of place. 



TABLE 27. 
For Estimating Size of Coal-Bin. 





Cubic Feet in One Ton. 


Kind of Coal. 


Short Ton, 2,000 lbs. 


Long Ton, 2,240 lbs. 


Broken 

Egg 
Stove 
Nut 
Pocahontas 


33. 
33.6 

34.2 

35. 

36. 


37. 

:;7.(; 
38 2 
39.2 
40.2 



The folio-wing is from tests by Mr. D. P. Sullivan, Sealer of Weights 
and Measures, Boston, Mass. 



Kind of Coal. 


One Ton. 


Cubic Feet. 


Cubic Inches 


White Ash 




Stove 


37 


116 


White Ash (egg) 




Stove 


36 


36 


Shamokin 




Stove 


37 


662 


Lackawanna (nut) 




Stove 


31 


857 


Franklin ( Ljkens Valley) 


Stove 


38 


164 


Lehigh (hard egg) 




Furnace 


33 


576 


Lehigh (free burning) 




Furnace 


36 


62 


Lackawanna (free burning) 


Furnace 


38 


796 


New River 




Soft Steam 


36 


1295 


Cumberland 




Blacksmiths' 


30 


723 



INDEX 



PAGES 

Air, amount heated 75, 98 

amount for respiration . . 24, 27 
amount for ventilation . . 28,41 

carbonic acid in 24-29 

carbonic oxide in 25 

circulation of 

. . . .35, 44-52, 54, 57, 58, 59, 65 

composition of 24, 25 

humidity of 28, 29 

impurities in 24-27 

leakage in school-rooms 

51, 54, 55, 61 

lime water test for carbonic 

acid in 29-32 

measurement of ... . 33, 35—39 
nitrogenous poison in. . . 25, 26 
supply for school-rooms- . 

50, 60, 61, 62 

temperature of 

... 38, 39, 48, 49, 60, 61, 62, 75 
valves in radiators .... 96 

velocity at inlets . .36,37,51,52 

vitiated by lights 29, 53 

volume and weight . . . . 39, 48 

Anemometers 33-37 

Appropriation for building . . 6 

Architects competition plans by . 2,6 
Architects to file plans with 

inspector 3 

Automatic heat control . . 98, 99, 100 

Basements 11, 12 

Bicycle runs 12 

Blackboards 22 

Boiler, care and management of 

115-117 

cast iron 76, 86, 87 

coal burned by ... . 74, 75, 78 

construction of 75-80 

covering 185 

fittings required for . . . 87, 92 
and furnace rooms . . . . 11, 12 

grates for 75, 76, 78 

heating surface of . . . 76, 77, 78 
horse-power of . 74, 81, 82. 83, 89 
horizontal tubular . 76, 77, 81, 82 

inspection of 90-92 

Massachusetts laws relating 

to 91, 92 

Massachusetts inspectors' 

rule for pressure .... 85 

U.S. standard for pressure 85 

plans of settings for . 186-189 

safety valves for 

80, 87, 91, 92 

settings for ... 83-85, 186-189 



Boiler, size of 81, 82 

smoke flues for 76-79 

tubes for 76, 79 

upright tubular 76, 86 

water tube 86 

Building Committee, appoint- 
ment of 2, 6 

Building, construction of . . . S, 9 
Care of heating apparatus . . 108-119 
Casings for furnaces .... 103, 137 

for radiators 96, 97 

Cast iron furnaces 102 

Cast iron sectional boilers . . 86, 87 

Cast iron registers 64, 195 

Chemical laboratories .... 12 

Chimneys . . . . 57, 58, 66-69, 71-73 
Circulation of air 35, 44, 46-54, 57-59,65 

Clocks 22 

Clothing-rooms 12, 13 

Coal, amount burned . . . 74, 75, 78 
Cold-air rooms . . . 12,'105, 109, 110 
Combination of furnace and fan 

. . . 105, 106 144, 146, 147, 148 
Combination of furnace and 

steam heat 

105, 144, 146, 147, 148, 152, 153 

Corridors 12, 13 

Cost of fuel 62 

of ventilation . . .42, 44, 62, 75 
Dampers . 53, 54, 64, 65, 68, 111, 118 
Deflectors and diffusers .... 53 

Desks 19, 20, 21 

Ducts and flues, foul air . . . 

52, 54-58, 61, 62, 66-70 

Ducts and flues, warm air 51, 52, 63-65 
Engineers and firemen, licensed 88-90 
Erroneous ideas of ventilation . 42-44 

Exits 14, 15 

Fans 50. 56, 69 105, 106 

Fire, means for preventing 

spread of 3, 9, 10, 11 

Fire escapes on school houses . 15 

Figures, 1-9, school house . . 

furniture 19, 20, 21 

10, Professor Wolpert's Air 
Tester 30 

11, Lime Water Apparatus 32 

12, Template for correcting 
anemometer 34 

13 and 14, Form of air inlet 35 
15. 16. 17 and 18, measuring 

air with anemometer . . 36, 37 
19, 20, 21. location of inlets 
and outlets and circulation 
of air in school-rooms . 47, 48 



INDEX. 



203 



V j T-. PAGES 

t iremen and Engineers, licensed 88-90 

Flap valves 54 55, 58 

Foot warmers 13, 184,'l85 

Furnaces, cast-iron 102 

and fan, combination of 

105, 106 

grates for J01 

and hot water, combination 

. of 105, 106 

location of . . . 101, 103, 104, 111 

management of 117-119 

Pipes for 1 05 

P lt for 103 

regulating temperature of 

103, 104 

setting of 103 

size of 10i 

smoke pipes 103, 104 

and steam-heat combination 

of 105 

test for gas leakage .... 102 

twin connected 105 

wrought iron 102 

use of, in school buildings 101 
Galvanized iron, dampers ... 54 

iron, size and weight of 

sheets 198 

iron vent-flues 58 

Gas engines 106 

lights 53 

Glass 13, 16 

Grates, boiler 7.-,, 76, 78 

furnace 101 

Heat, automatic control of . . 98-100 

in vent flues 

.... 66-70, 106, 107, 111, 112 
Heating apparatus, location of . 53, 54 

cost of 02 

Height of school buildings . . 7, 8 

Inlets, air. form of 35 

air, location of . 44, 46-49, 58, 64 
air, size of . . . 51, 60, 61, 63, 64 
Janitors, duties of and instruc- 
tions for 108-1 19 

Leakage of air 51,55,56 

Lime water test for purity of air 29-31 
apparatus for preparing . . 31-33 
Location of air-inlets and outlets 

35. 44, 

46-49, 58, 60, 61. 63, 64, 65, 68, 70 
of heating apparatus 53, 104, 105 
of school buildings . . 1, 6, 7 
Massachusetts laws for construc- 
tion of buildings . . . 2, 3, 4, 5 
laws for inspection of steam- 
boilers 90, 91, 92 

laws for licensing engineers 

and firemen .... 88, 89, 90 
requirements to prevent 

spread of fire .... 9, 10, 11 
requirements for ventilation 
5, 41, 42 



m , . PACES 

Measurement of air ... 33, 35_38 
Mixing dampers and valves . . 

ra • ; 68, 64, 104, 106 

Flans for and descriptions of 

schoolhouses, Part II. 127 

Plates. 

I, one-room schoolhouse 128-130 
II and III, one-room portable 

schoolhouse 130-133 

IV, V and VI, two-room, 

one-story schoolhouse, 133-139 
VII, VIII and IX. two-room 

two-story schoolhouse. 139-144 
X, XI. XII, XIII and XIV, 
four-room, two-story 

schoolhouse I44_i4g 

XV, XVI and XVII, five- 
room, two-story school- 
house 148-154 

XVIII, XIX and XX, six- 
room, two-story school- 
house 153-156 

XXI, XXII, XXIII, XXIV, 
seven-room, two-story 

schoolhouse 156-162 

XXV, XXVI, XXVII and 
XXVIII, eight-room, two- 
story schoolhouse . . . 162-166 
XXIX. XXX, XXXI, and 
XXXII, eight-room, two- 
story schoolhouse . . . 166-171 
XXXIII, XXXIVandXXXV 
small high or a grammar 

schoolhouse 171-179 

XXXVI and XXXVII sani- 
tary buildings .... 180, 181 

XXXVIII, direct-indirect 
radiator 179-182 

XXXIX. portable furnace 
for small hall or church 

183, 184 

XL, foot-warmer for school- 
house corridor .... 184, 185 
XLI, XLII and XLIII. set- 
ting for one horizontal 
tubular boiler .... 186-188 
XLIV, section of setting 
for two horizontal tubular 

boilers 189 

Plans, competition 2, 1; 

to be filed with inspector. . 3 

Plenum and exhaust systems .... 

50, 51, 55 

Prevention of spread of fire . . 

3, 9, 10, 11 

Radiation, direct 97, 98 

direct-indirect 97 

indirect 95-97, 99, 100 

Radiators, casing 95-'.'7 

cast-iron . 70, 95, 96 

piping 70, 93 

Rooms 17, 18, 23 



204 



INDEX. 



PAGES 

Sanitary buildings and fixtures, 

care of 120-126 

Seats 18, 19, 20, 21 

Stairs 12, 14, 15 

Stack-heaters . 68, 69, 106, 107, 119 

Steam-pipes 69, 70, 93-95 

Steam-valves 94, 96 

Systems, defective 42-46 

exhaust and plenum . 50, 51, 55 
Tables 

1, for Wolpert's air test . . 31 

2, of wind velocity and 
pressure 40 

3, of tests of amount of 
heat and air in school- 
houses 60 

4, of tests of amount of 
heat and air in school- 
houses 60 

5, of tests of amount of 
heat and air in school- 
houses 61 

6, of tests of amount of 
heat and air in school- 
houses 61 

7, relative cost of fuel in 
schoolhouses 62 

8, of boiler, grate and 
heating surfaces 76 

9, of area of grate surface 

and tube opening .... 76 

10, of standard boiler tubes . 77 

11, standard sizes of boilers 
81, 82 

12, of dimensions of brick 
settings boilers 84 

13, of dimensions of brick 
settings boilers 85 

14, of sizes of supply and 
return steam-pipes .... 93 

15, of areas of rectangular 
openings 190, 191 

16, of areas and circumfer- 
ence of circles 192 



PAGES 

Tables: 

17, for equalizing diameter 

of pipes 193 

18, of number of gallons in 
round tanks and cisterns . 194 

19, of capacity of pipes and 
registers 195 

20, of weight of steel bars 

per foot 196 

21, of standard gauges . . . 197 

22, of weights of galvanized 
sheets 198 

23, of circumferences of 
circles used by boiler 
makers . 199 

24, of number of tubes used 

in return tubular boilers . 199 

25, of dimensions of stand- 
ard wrought-iron pipe . . 200 

26, of expansion of metals . . 200 

27, for estimating size of 

coal bins 201 

Temperature in school-rooms 

41, 60, 61, 62, 118 

Thermometers 22 

Try-cocks in water-pipes ... 11 
Ventilation, Massachusetts re- 
quirements for 41, 42 

erroneous ideas of . . 42, 43, 44 

systems of 45, 46 

Vent-ducts, flues and shafts . . 

.... 54, 56, 57, 66-70, 106, 107 

Vestibules 14 

Warm-air ducts and flues . . . 63-65 

Water-motors 106 

Wind, action on chimneys and 

vent-flues 63-65 

varying conditions of . . . 56, 70 
velocity and pressure . 39, 40, 56 

Windows 13, 16, 17 

Wire grills . . . . 64, 65 

Wolpert's air test . .... 29,30,31 
Wooden flues and ducts, not 

allowed 3 



NOV 25 1905 



